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starks Offline
#1 Posted : Sunday, 2 July 2017 7:56:12 PM(UTC)
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Hi guys, needing some thoughts on timing..

Im running an msd pro billet in my 308 15° intial 33° total no vac advance which I know is basic ballpark for a 308. Need to change springs and speed up the advance curve slightly.


Engines getting about 14 hg vacuum at idle,
Has estimated 10:5.1 compression, pre pollution heads with l34 valves and a bowl job. 40thou over flat tops running a crane 276 218°at .050, 472 lift bumped up by yella terra rockers and edelbrock manifold with quadrajet. In a hz ute.

Idle circuit still smells rich (gonna go up 2 sizes on primary rods on the quaddy to help clean up idle a little) and she will take more initial without pinging. Im looking to hook up vacuum advance to direct manifold vacuum as i street drive her a couple of days a week and think it could benefit. Msd dissy runs a 12° vac advance can. Thinking of running 12 intial plus 18• or 21° mechanical bush so 30- 33 total plus vac advance. In theory this will give 24 ° initial at idle though. Is this too much or am I better off with the later factory 8• plus vac advance?

Im sure factory set pre pollution 308s were 12° plus vac advance and post pollution was 8° after holden retarded the cam timing. Im aware to as much as 9°. Plus smaller duration cam etc.

Any thoughts here would be great thanks

Edited by user Sunday, 2 July 2017 7:58:19 PM(UTC)  | Reason: Not specified

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#2 Posted : Sunday, 2 July 2017 8:23:26 PM(UTC)
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Auto or manual? If you use ported vacuum you won't get the advance at idle if it is a manual. Auto normally need more advance at idle to overcome the converter.
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starks Offline
#3 Posted : Sunday, 2 July 2017 8:26:51 PM(UTC)
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Shes auto, running a 700r4 and all the low rpm running fowls the plugs a bit.
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#4 Posted : Sunday, 2 July 2017 8:28:27 PM(UTC)
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Oh and 2500 converter
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#5 Posted : Sunday, 2 July 2017 8:46:10 PM(UTC)
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Originally Posted by: starks Go to Quoted Post

Im sure factory set pre pollution 308s were 12° plus vac advance and post pollution was 8° after holden retarded the cam timing. Im aware to as much as 9°. Plus smaller duration cam etc.



The early 308's including L34 had the smaller cam, they used the 253's cam but retarded 5deg. For HJ a larger cam was installed and all 308 and 304 used that cam and the old 253's cam gear right up until the end of the carbied V8 in VL except for the VK Group A. It wa sthe 253 where they buggered around with different cams.

HT 308 initial timing was 2 deg, later revised to 6deg. HQ and HJ is the same although the mechanical advance curves are different. HX is 6deg manual, 3 deg auto but also quote 12deg@1350rpm. Blue and black engines differ again.

As you have an auto it shouldn't suffer as bad at idle as a manual with with full vacuum source for vacuum advance. The higher stall might make some difference though.

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starks Offline
#6 Posted : Sunday, 2 July 2017 9:48:26 PM(UTC)
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Originally Posted by: HK1837 Go to Quoted Post
Originally Posted by: starks Go to Quoted Post

Im sure factory set pre pollution 308s were 12° plus vac advance and post pollution was 8° after holden retarded the cam timing. Im aware to as much as 9°. Plus smaller duration cam etc.



The early 308's including L34 had the smaller cam, they used the 253's cam but retarded 5deg. For HJ a larger cam was installed and all 308 and 304 used that cam and the old 253's cam gear right up until the end of the carbied V8 in VL except for the VK Group A. It wa sthe 253 where they buggered around with different cams.

HT 308 initial timing was 2 deg, later revised to 6deg. HQ and HJ is the same although the mechanical advance curves are different. HX is 6deg manual, 3 deg auto but also quote 12deg@1350rpm. Blue and black engines differ again.

As you have an auto it shouldn't suffer as bad at idle as a manual with with full vacuum source for vacuum advance. The higher stall might make some difference though.



It must be the 12° at 1350rpm i had in my head from an older manual.
I had a factory holden manual from early commodore I think that stated 6° on L6 engines and 8° on V8.
Every source of material ever published seems to just about differ though haha. Could be as things changed with emissions over time those manuals change and cloud perceptions.

So whats thoughts on where I should set my intial before vac advance? Just so I can work that figure into my total timing for my mechanical advance?

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#7 Posted : Monday, 3 July 2017 5:59:45 AM(UTC)
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As you're running very different specs to factory (compression, cam etc) factory settings are a waste of time. Use them as a starting point only.

You probably need less initial advance to cope with the compression.

Fuel choice is a much bigger factor too - if you're going to put premium in it, you'll be able to run more advance, but if you're only going to run 91, it won't be happy unless you take some out.

As an example, EFI 5Ls ask for 10° static advance, but around 14° seems to make most of them happy (some don't like more than 12°).
Run them on premium, and those 12° one will cope with 14° no problems - and run happier.

Carby 304/308 as you say seem to vary all over the shop. 8-10° was where I used to always set stock blue & black as a starting point, and work up from there.

In the 90s when we still had proper leaded fuel for a while, I was able to run 12° on a blue 308 with increased compression & a small-ish cam. I can't remember what the comp was now - but it would have been in the low 10s probably. As they took the lead out of petrol, I found myself winding back the static timing due to pinging when going up a decent hill near home in 2nd gear. I ended up with no more than 6° when running that LRP stuff Mobil used to offer for leaded cars.


As far as the total mechanical advance, the guys who regraph dizzies for a living will know where to aim for, so someone may chime in. Unless you're dyno tuning it, they'll only be giving you a (very) educated guess based on your mods, and their experience, but the guys who have been doing it a long time will get it pretty close, if not spot-on.

I have a stroker (304>346) running straight gas, increased comp, and a fairly mild Wade 242A cam. Because of the gas, it takes way more static advance, but much less overall. It wasn't expensive to have the dizzy recurved by a reputable workshop (owned by one of the contributors on here).
Cheers,

Mick
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starks Offline
#8 Posted : Monday, 3 July 2017 6:40:30 AM(UTC)
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Originally Posted by: commodorenut Go to Quoted Post
As you're running very different specs to factory (compression, cam etc) factory settings are a waste of time. Use them as a starting point only.

You probably need less initial advance to cope with the compression.

Fuel choice is a much bigger factor too - if you're going to put premium in it, you'll be able to run more advance, but if you're only going to run 91, it won't be happy unless you take some out.

As an example, EFI 5Ls ask for 10° static advance, but around 14° seems to make most of them happy (some don't like more than 12°).
Run them on premium, and those 12° one will cope with 14° no problems - and run happier.

Carby 304/308 as you say seem to vary all over the shop. 8-10° was where I used to always set stock blue & black as a starting point, and work up from there.

In the 90s when we still had proper leaded fuel for a while, I was able to run 12° on a blue 308 with increased compression & a small-ish cam. I can't remember what the comp was now - but it would have been in the low 10s probably. As they took the lead out of petrol, I found myself winding back the static timing due to pinging when going up a decent hill near home in 2nd gear. I ended up with no more than 6° when running that LRP stuff Mobil used to offer for leaded cars.


As far as the total mechanical advance, the guys who regraph dizzies for a living will know where to aim for, so someone may chime in. Unless you're dyno tuning it, they'll only be giving you a (very) educated guess based on your mods, and their experience, but the guys who have been doing it a long time will get it pretty close, if not spot-on.

I have a stroker (304>346) running straight gas, increased comp, and a fairly mild Wade 242A cam. Because of the gas, it takes way more static advance, but much less overall. It wasn't expensive to have the dizzy recurved by a reputable workshop (owned by one of the contributors on here).


Fuels ok, ever since I owned the ol girl back running a 253 shes only ever seen BP ultimate.... except for one occasion when I was low on fuel and thought shell premium would be ok, nope rattled her head off so all she sees is Bp ultimate now.

Mecahical timing I can play with ok as the MSD distributor gives me the ability adjust the mechanical advance and the speed of advance. The dissys currently running heavy silver and a light blue spring but feeling things will get me all in by 3000rpm by changing to a silver heavy and silver light spring but that depends on which mechanical advance bush I use.

So Im thinking if I set 8° intial and use a 25° mech advance bush that will give me 33° total which is ok.
When I add vac advance at 12° that will give me vac plus intial 8° which will give me 20° at idle.
Then I just need to find an advance rate that suits with different springs. Light blue and light silver will give me all in by 3000rpm, heavy silver and light silver all in by around 4000rpm.

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#9 Posted : Monday, 3 July 2017 8:22:10 AM(UTC)
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Where are you located? The guys at Chiptorque told me last month that they find in Brisbane-ish area (basically border to Sunshine Coast) BP Ultimate is the best fuel, but only if bought from Corporate BP servos (those with BP shops) as smaller ones may not have the same quality. In Sydney-ish (Wollongong to Newcastle) that Shell Premium is the best. By best they mean less knocking so knock sensor works less. This is based upon them being in the Gold Coast area and using local fuel, and I think people bringing fuel with them from down south when vehicles are modded and dynoed up there so the cars are tuned to their local fuel.
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starks Offline
#10 Posted : Monday, 3 July 2017 9:25:56 AM(UTC)
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Originally Posted by: HK1837 Go to Quoted Post
Where are you located? The guys at Chiptorque told me last month that they find in Brisbane-ish area (basically border to Sunshine Coast) BP Ultimate is the best fuel, but only if bought from Corporate BP servos (those with BP shops) as smaller ones may not have the same quality. In Sydney-ish (Wollongong to Newcastle) that Shell Premium is the best. By best they mean less knocking so knock sensor works less. This is based upon them being in the Gold Coast area and using local fuel, and I think people bringing fuel with them from down south when vehicles are modded and dynoed up there so the cars are tuned to their local fuel.


Im on the south side of brisbane and always use the bp about 5 minutes from home. Its a reasonable size service station. The fuel quality from there seems to be working well.

Funny about the shell premium in sydney area, had someone down there tell me they found it was about as good as united fuel in their track car and werent surprised my engine rattled when I ran it. As you say though just depends on your local fuel.
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#11 Posted : Monday, 3 July 2017 9:49:12 AM(UTC)
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I was only going by what Bullet and Chiptorque told me when I fitted the blower to my Hilux, and Chiptorque tuned it for me. It has over 10:1 compression and around 7psi of boost so it will ping on any 98 under the right (or should be wrong) scenarios, but the knock sensor pulls timing back very quickly plus I have a low octane switch so I can knock timing out if I get some dodgy fuel or if I can only get E10 or 95. I haven't noticed any real difference between any 98 Octane local to me, but I won't buy it from dodgy looking servos or non-branded ones like 7-Eleven anymore. I must say though, I filled it up with BP Ultimate at the Nerang BP, and topped up again at the new BP at Warwick on the way back and I didn't notice any pinging. So I'd use BP where you are, as the local tuners like Chiptorque are the ones who will know which is the best fuel to use.
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#12 Posted : Saturday, 14 April 2018 10:39:05 AM(UTC)
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Originally Posted by: HK1837 Go to Quoted Post
Originally Posted by: starks Go to Quoted Post

Im sure factory set pre pollution 308s were 12° plus vac advance and post pollution was 8° after holden retarded the cam timing. Im aware to as much as 9°. Plus smaller duration cam etc.



The early 308's including L34 had the smaller cam, they used the 253's cam but retarded 5deg. For HJ a larger cam was installed and all 308 and 304 used that cam and the old 253's cam gear right up until the end of the carbied V8 in VL except for the VK Group A. It wa sthe 253 where they buggered around with different cams.

HT 308 initial timing was 2 deg, later revised to 6deg. HQ and HJ is the same although the mechanical advance curves are different. HX is 6deg manual, 3 deg auto but also quote 12deg@1350rpm. Blue and black engines differ again.

As you have an auto it shouldn't suffer as bad at idle as a manual with with full vacuum source for vacuum advance. The higher stall might make some difference though.



Oh just came across this, Anxious I will put it out as to camshaft position in regard to the crank position is the first starting point.
So if we retarded a camshaft timing one would be looking at that in direct relationship to the starting point of the dizzy.

From what I remember was HT 308 stated 2 deg and then this went up to 6 deg with the HQ and then 12 deg with the HX if correct.

Now the why did they do this ?

I would like to have all the info on the years to look at so as to work out what was truly going on.

If you retard a cam then you have to advance the dizzy.

When a cam chain gets worn out then what happens is that the cam will be end up being more retarded ?

With the 253 HT it must be about 7 deg ? and the stock L34 ? the same, I don't remember seeing any 12 deg till the HX came out.

This brings me to the point of the HJ 308 vs HX 308, they both have the same cam but I think that the HX should be retarded cam of 6 deg more making the dizzy 12 deg, the HQ HJ should be about 6 deg factory with 0 deg cam, or are they ?

When the HJ came out the ADR27 came about and they had to change the camshafts to suit and we see that there is more duration added to the end of the intake valve closing, this is to promote more heat in the exhaust to burn more of the un burnt fuel only and this is why the 308 static compression had to go up from 9.0 to 9.7 now the point of all this is that the dynamic compression has not moved up at all in truth of all this.

If one was to retard a stock 308 HQ cam say by 6 deg you will end up loose dynamic compression.

A HT to HQ 253 that has the same cam as the HT-Q 308 would have a lower dynamic compression than the 308 even tho they both have the same 9.0 static compression.
Now why did Holden do such a thing ?

Then their is the advance curves and Vacuum advance setups to deal with, not to mention with the HX on the ADR27A and on of cold running restrictions and why they do such a thing and top gear is open.
It's all interesting to me.

In the USA from 1966 on their has been emission laws, it's interesting what they did, even air pumps in some earlier than 1973 where this adds air into the exhaust manifold so as to create more heat to burn of the un burnt fuel and even with cat converters in 1975 when they first came out.
We got the Air pump in 1984 in the 173 VH and the carby VK 202 and then the cats from 1986 in the VL.

I was looking into the Ford Cleveland 351's in the USA it's great to see the difference because by 1972 they had to claim the power figures in Net so you can see the reality of what is happening with each car and why it does show a less power in some cars with the same engine in it, due to single exhaust or dual and even the 1973 with when EGR came out, and the 4V heads with smaller valves.

EGR does not look to harm total power really but the air pumps do knock a bit off.

When one looks to our HX 308 it was a dog gutless to the ones before it but then again it always was a slug with a single exhaust.
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#13 Posted : Monday, 16 April 2018 8:17:19 PM(UTC)
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308 initial timing is as I stated. HT started at 2deg, and it was revised to 6deg where it stayed for HG-HJ but curves are different. HX is as I stated too: 6deg manual, 3deg auto @900rpm however it is also quoted from memory at 12deg@1350rpm for the later (post 10/77) engines which is essentially HZ engines.

HT 253 4deg for the LC engine and 6deg for the HC engine.

L34, I can't find my docs at the moment, it had similar compression to the HJ engine so should be similar.

All the timing gears were the same going from memory except for HT-HQ 308 which was retarded 5deg. There was a change made to the 253's timing gear with the XT5 engine (blue) but can't remember exactly what it was. Will check.

ADR27 didn't come with HJ. It was introduced approx. 8-9/73, which is why the last XU1's were built prior to the new clean air engines. This is when the HQ's carbies were revised, HJ just carried on the same other than the better cam and more compression. Simple as that. This added about 20-25hp, although GMH never said anything about it.

The reason the HT-HQ 308's cam was retarded was to generate a higher peak power as they wanted to keep the same cam between 253 and 308 for economies of scale. They tested bigger camshafts for significantly more power but decided to keep it the same as the 253 and retard it. The part number on the HJ 308 cam fits exactly into this later development period. The 308 was upgraded after HQ as there was no longer a 350ci engine and they needed more power and torque especially for Caprice.

AIR (essentially ADR27) became mandatory on all 1968 models in the USA. This is why we got unique carbs on 327 and 350 after the early HK ones as the tune was different. HQ 350 got a US spec carby from 8/73 as we then went to US emissions specs (lean idle for one part).
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#14 Posted : Tuesday, 17 April 2018 11:19:46 AM(UTC)
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Originally Posted by: HK1837 Go to Quoted Post
308 initial timing is as I stated. HT started at 2deg, and it was revised to 6deg where it stayed for HG-HJ but curves are different. HX is as I stated too: 6deg manual, 3deg auto @900rpm however it is also quoted from memory at 12deg@1350rpm for the later (post 10/77) engines which is essentially HZ engines.

HT 253 4deg for the LC engine and 6deg for the HC engine.

L34, I can't find my docs at the moment, it had similar compression to the HJ engine so should be similar.

All the timing gears were the same going from memory except for HT-HQ 308 which was retarded 5deg. There was a change made to the 253's timing gear with the XT5 engine (blue) but can't remember exactly what it was. Will check.

ADR27 didn't come with HJ. It was introduced approx. 8-9/73, which is why the last XU1's were built prior to the new clean air engines. This is when the HQ's carbies were revised, HJ just carried on the same other than the better cam and more compression. Simple as that. This added about 20-25hp, although GMH never said anything about it.

The reason the HT-HQ 308's cam was retarded was to generate a higher peak power as they wanted to keep the same cam between 253 and 308 for economies of scale. They tested bigger camshafts for significantly more power but decided to keep it the same as the 253 and retard it. The part number on the HJ 308 cam fits exactly into this later development period. The 308 was upgraded after HQ as there was no longer a 350ci engine and they needed more power and torque especially for Caprice.

AIR (essentially ADR27) became mandatory on all 1968 models in the USA. This is why we got unique carbs on 327 and 350 after the early HK ones as the tune was different. HQ 350 got a US spec carby from 8/73 as we then went to US emissions specs (lean idle for one part).


I agree with the 9/1973 ADR27 would be true, so that makes all them engines on the same as the HJ. I don't believe they are better cams tho, they are just pollution cams and the only reason why the 9.7:1 static compression is to keep it the same Dynamic compression as the HT-G-Q. The longer the valve opens past only losses dynamic compression and that's a fact and it just works out this is correct. SAE is said to be 10 HP more in the 308 HJ but in Net or DIN HP it may be nothing especially a single exhaust 308.

The keep this HJ cam in the HX 308 be it's been tampered with in relation to the advancing or retarding of it I wonder but I think it's the same as the HJ in that regard, now the HX 10/1977 on were regarded as a better tuned HX and the same as the HZ, must mainly be down to the dizzy setup ? that they got their act together or also the carby jetting, the XC Ford V8 get updated tune about the same time as well and perform better as well and I know that the carby was altered, maybe the dizzy as well, not to mention when the electronic dizzy came in the 5.8L would of helped but the 302 XC only had points.

When the HJ 308 came out I never heard anyone say they went better than earlier 308's especially the HJ 308 auto was considered more of a slug and a mate had one in a HJ ute seamed to like to rev a bit more and he had dual exhaust on it and a mates HQ 308 GTS auto and dual exhaust would eat it, I drove both flat out dragging others and around the place, HQ had more grunt down low for sure and only up over 5000RPM I would say that the HJ was happy to rev, not that it would perform better to 5000RPM.

The smog pump came in California (AIR) 1974 was when other States got that and 1973 was EGR then cats in 1975.

The Last of the HQ 350 were slugs, a mate had a 1973 4sp GTS nice car and all but he knew 308's could hose him off, he did not like to admit it but it was true.
The problem was that the late 350's were gutless pollution engines as that's all that Australia could get, so the HJ 350 was a dead duck with no point of putting junk like that up against a 308.
Just as we all know that once ADR27A came in the 308 was a total slug and gutless as.
A mate had a fully stock HX 5.0L 4sp Sandman ute what a gutless petrol chewing slug, he just could not believe it when he drove my 308 he still rants about that even nowadays.

Why HT-G-T-Q Holden V8's cam was the same and just played with the cams timing point is of interest to me.

I don't think that it had to do with economies of scale to only have one cam grind, for one the 6 cyl has auto and manual cams from HT to HZ, not to mention why go smaller cam with the 253 from 9/73 but extend the intake closing timing, such is to do with emissions in fact, and the reason why they do such is only due to try to make more heat in the exhaust to burn up more unburnt fuel to lower emissions.
No way could one say that the HJ 253 would perform better, but it may be said that she lost some power 185hp to 175hp SAE gross and no better on fuel.

Changing the cam spec makes no sense from 9/73 apart from emissions when you understand what such is actually doing, it's not a performance grind intent at all, because everything points to just heating up the exhaust for emissions, some what like a cat does and that's why the(AIR) smog pump cam about, so as to heat up the exhaust burning off un burnt fuel, they in the USA used this with cats as well in 1975.

With the 5.7L Gen 3 you will see that they retard the cam timing in the VY series 2 this went from 235KW to 245KW but the 245KW did not perform as well as the 245KW through the rev range as was the same with the VZ 250KW, the 235KW could hose them off, the VZ even had to lower it's gearing or the fact would of been obvious.
I had runs with 245KW ute and 250KW ute, thing is that the VZ ute did not lower the diff ratio like they did in the sedan and when a mate came out to hose me off even I was shocked to find that he did not have a hope, and that say 3dr gear runs, proving that nothing could be in it as to driver skill, but only that the 250KW had lost some grunt and the extra KW up top was truly just useless.

Most people believe that the max HP is where it's all at but fact is it's not.
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#15 Posted : Tuesday, 17 April 2018 1:57:18 PM(UTC)
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No, HJ engines don't start until HJ production. 8/73 on HQ engines are the same just different carbs for ADR27. They are 100% a better cam, not a pollution cam at all. The HJ on 308/304 cam is exactly the same grind cam as used in 307/327 and 350 engines from the 60's once hydraulic cams became the norm. Used right up into the performance 327 and 350 (327/275hp and 350/300hp). Same cam used on the 8.5:1 HQ 350, the 8.75:1 307 and the 8.5:1 327, 9:1 327, 9.75:1 327 and 10.25:1 350. There was only one other higher performance hydraulic cam and that was the Corvette's 350/350hp cam.

Internals weren't touched with ADR27A, it was only external so the 308 remained the same internally in the HX (other than the exhaust crossover ports). Only the externals changed, and this was where all the power was lost.

HZ intake manifold was made far better than the horrible one on the HX. Plus they changed the carby tune a little, and had a different dizzy curve.

HJ went far quicker than a HQ, but you will hardly find tests on the engine. I know of only two proper tests, one on a dual exhaust GTS where the journos were floored over how quick it was compared to a HQ. The other where they got an early LX SS 5.0L manual, and couldn't believe how quick it was compared to the original LH SLR5000 with the HQ engine.

Last 350's were slugs compared to HT-HG but all HQ's were that way as they were all 1972 spec USA pollution engines, but if tuned properly no 308 would touch one. Remember the HQ 350's were only ever really fitted with 2.78 or 3.08 rear axles for manual or auto, whereas HQ's got a 3.36 rear axle with a manual. Put a 3.36 rear axle in a stock HQ 350 manual and you'd be surprised how quick they were. The last 350's were actually better than the early ones, in the USA they were rated for higher hp - the heads were improved over the 1971-1972 spec engines.

Go and find the original Engineering report on the development of the 253 and 308. They state in there that the same cam was retained for 308 as 253 for cost purposes as they could retard it and get their target peak figure. They even state that more power was easily gained from the 308 with a bigger cam but they had no need for it (yet). The HJ 253 is identical to the HQ 253, it didn't change other than the carby change during HQ. The 253 didn't change until HX where it got more compression. The power figures changed in HJ as they revised them all downwards from the HQ figures closer to their true figures, apart form the HJ 308 which they revised upwards. The HQ 308 dynode by Holden at about 225hp (curves are in Norm Darwin's books), but they changed it to 240hp. HJ was a true 250hp and it continued to make power after the HQ fell away - this is all about the cam and higher compression.
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#16 Posted : Tuesday, 17 April 2018 3:21:20 PM(UTC)
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I found the L34 stuff. Dizzy was the same mechanical advance curve as the HQ engine (early LH), but had no vacuum advance. Initial timing quoted as 3deg@500rpm and 7deg at 800rpm.
Cam remained as per the HT-HQ with the same retarded 5deg cam pulley. The L34 also kept the same tiny dual exhaust as the LH V8 SLR, and the same carby also but with mechanical choke. The cam was free for 1973 onwards GroupC, as was the exhaust from the first joint and the carby was too thus there was no need to change these on the production car.

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#17 Posted : Tuesday, 17 April 2018 5:55:02 PM(UTC)
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Also just found the XT5 timing gear stuff. It looks like there is 2.5deg difference between the cams when installed. The 4.2L one is rotated 2.5deg anti-clockwise compared to the 5.0L one.
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#18 Posted : Wednesday, 18 April 2018 11:02:02 AM(UTC)
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Originally Posted by: HK1837 Go to Quoted Post
No, HJ engines don't start until HJ production. 8/73 on HQ engines are the same just different carbs for ADR27. They are 100% a better cam, not a pollution cam at all. The HJ on 308/304 cam is exactly the same grind cam as used in 307/327 and 350 engines from the 60's once hydraulic cams became the norm. Used right up into the performance 327 and 350 (327/275hp and 350/300hp). Same cam used on the 8.5:1 HQ 350, the 8.75:1 307 and the 8.5:1 327, 9:1 327, 9.75:1 327 and 10.25:1 350. There was only one other higher performance hydraulic cam and that was the Corvette's 350/350hp cam.

Internals weren't touched with ADR27A, it was only external so the 308 remained the same internally in the HX (other than the exhaust crossover ports). Only the externals changed, and this was where all the power was lost.

HZ intake manifold was made far better than the horrible one on the HX. Plus they changed the carby tune a little, and had a different dizzy curve.

HJ went far quicker than a HQ, but you will hardly find tests on the engine. I know of only two proper tests, one on a dual exhaust GTS where the journos were floored over how quick it was compared to a HQ. The other where they got an early LX SS 5.0L manual, and couldn't believe how quick it was compared to the original LH SLR5000 with the HQ engine.

Last 350's were slugs compared to HT-HG but all HQ's were that way as they were all 1972 spec USA pollution engines, but if tuned properly no 308 would touch one. Remember the HQ 350's were only ever really fitted with 2.78 or 3.08 rear axles for manual or auto, whereas HQ's got a 3.36 rear axle with a manual. Put a 3.36 rear axle in a stock HQ 350 manual and you'd be surprised how quick they were. The last 350's were actually better than the early ones, in the USA they were rated for higher hp - the heads were improved over the 1971-1972 spec engines.

Go and find the original Engineering report on the development of the 253 and 308. They state in there that the same cam was retained for 308 as 253 for cost purposes as they could retard it and get their target peak figure. They even state that more power was easily gained from the 308 with a bigger cam but they had no need for it (yet). The HJ 253 is identical to the HQ 253, it didn't change other than the carby change during HQ. The 253 didn't change until HX where it got more compression. The power figures changed in HJ as they revised them all downwards from the HQ figures closer to their true figures, apart form the HJ 308 which they revised upwards. The HQ 308 dynode by Holden at about 225hp (curves are in Norm Darwin's books), but they changed it to 240hp. HJ was a true 250hp and it continued to make power after the HQ fell away - this is all about the cam and higher compression.


8/73 engines are the same as HJ just look at them they have the same PCV setup from then on and the new carb set for ADR27.

The HJ 308 is in fact a pollution cam and it can not raise the dynamic compression and that's why they went up from 9 to 9.7 to try to keep the dynamic comp the same, because of the loss, if they were just to keep it at 9.0 they would of lost more performance.

The 308 HJ cam is not the same grind as the Chev at all in fact if you look into it a bit more you will see it's not, and the chev has crappy exhaust port design but with a Holden that work well.
The ford and chev do put more valve lift and duration on the exhaust to help balance it out.
One cam grind for all engines does not work.

I have read the report years ago and it's nothing in depth at all but a short statement of such.

SAE HP figures are crap they are so wildly stated that such rubbish became obsolete back in 1972 even in the USA for crying out loud.
Now how could Holden of just changed the figure from 225 to 240 such is just BS at best, all I can say is the difference was nothing to wright home about at all and I never heard anyone say that the HJ went better than the HQ at all ever. I can only say that if felt a little livelier up top wanting to rev more, but this was out of it's rev range of where they made any worthy performance gains, like 1/4 mile.

A mate had a brand new LX SS 5.0L 4sp and it was as gutless as, twin pee shooters and all.
I have every test of cars of the time and I was always pissed off at the way the testing was done just 3rd rate shit! how many half arse test I came across, oh the car went off song or some other load of rubbish, if you are going to do a test get it f ing right I say, no room for blunders or shitty hopeless drivers times.
My uncle would give me German mags with test it was like cork and chees the Germans were like magic with everything and the Aussie test were just a backward joke done by some wally wombat that truly did not give a toss about the integrity of his work, she will be right most will not care.

All I can say is that I used to go out to drag others at the drop of a hat, so I know what went like what.

Old mate with 1973 HQ GTS 4sp 3.08 diff was gutless good torque but gutless he did not run my 308 because he knew I would win and his ego could just not take it and admitted such.
The HQ 350 had good torque but did not rev out well the same can be said of the ford 351 with 2V heads and 4 BBL all torque but rev them out and they dropped off the performance badly.
The XC 5.8L is said to be making more power than the XB GT 351 and I can tell you the XC sure did not perform as well and I have never come across anyone who says they did.
XC-D-E 5.8L were gutless, just as the HX on Holden 5.0L were all gutless even the VC Brock was gutless and a mate who still has one says they are gutless.

All 308's with single exhaust were gutless as from the HT on, you needed dual to get them to perform.

That HQ GTS 308 had a trimatic and the HJ on 308 suffered because of the hopeless Turbo 400 slush box that just killed performance not to mention was a total boring slow and dopy to use that you could not stand to drive the car with one in std form.

You can get a good performing engine and a bad one in any batch, seen it plenty of times stock as a rock factory car, one goes well and the other does not.
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#19 Posted : Wednesday, 18 April 2018 11:59:31 AM(UTC)
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Not sure how many times I have to say it. HQ AND HJ 308/5.0L ENGINES ARE NOT THE SAME. HQ 308 engines are HQ engines, end of story. HJ 5.0L engines are HJ 5.0L engines, end of story. A post 8-9/73 HQ 308 is identical in all ways to an earlier HQ 308. All that changed was a LEAN IDLE carby with sealed idle adjustment screws and the aircleaner got a vacuum operated hot air intake off the exhaust manifold stove. The PCV valve was there from way back, all that changed regarding that in 8-9/73 was the PCV intake took air from the aircleaner rather than through the oil filler cap. HJ engines used the same carby as the same HQ engine but got the far better cam and more compression, plus the 25 extra hp and about 10lb-ft as well, plus they kept making power way past where the HQ engine hit the wall - this is all to do with the cam. 1/75 HJ 5.0L carby changed, but only to seal the fuel bowl and vent it into the intake rather than to the atmosphere plus to facilitate a ported vacuum source on all 308 carbs so that the canister would function. Performance was identical to pre 1/75 HJ.

Garbage. HJ cam IS NOT A POLLUTION CAM. It is a Chevrolet general purpose hydraulic cam grind used on just about all SBC design V8 engines of the era (other than the 350/350hp Corvette (hydraulic) and the high performance Z28 or LT1 or similar engines (mechanical cam)), on all engines from compressions of 8.5:1 up to 10.25:1. GMH used the same cam profile on all 308/304 engines from HJ onwards, which included 9.7:1 HJ-HZ, 9.4:1 VB, 9.2:1 WB/VC-VK and 8.5:1 VK-VL, all with the same chambers, all with the same ports. The difference with the Hodlen V8 is they used 1.6:1 rockers, SBC were 1.5:1.

Chevrolet do not have a crappy exhaust port design, the later fuelies have better ports than a Holden V8 did standard. They worked well up to 370hp on an LT1.

That 253/308 development report is comprehensive, either you did not understand it or didn't read it properly.

Not getting into the HP figures again, except to say again you are getting it wrong, Gross figures are the only ones that make sense comparing engines as they are all tested using the same variables.

No BS, total fact. Again end of story. I have the dyno curves for the original 308 tests, IT IS NOT BS - it is fact. GMH raised the HT 308 peak figure to 240hp from about 225hp for advertising. They did it with all HQ engines, and this becomes even more obvious where they re-rate all the engines for HJ, they ALL drop in hp and torque other than the 5.0L which goes up. If the HJ 5.0L engine had remained the same as the HQ 308 it would have been re-rated down to 230hp or just under, just like the HJ 253 was de-rated (it didn't change from HQ). HJ 308 engine IS SUPERIOR to HQ engine, that is 100% fact and that comes from many sources from Engineering docs to road tests, so forgive me if your memory is not trusted on this. EVERYONE who owned a new HJ 5.0L will tell you they were superior to a HQ 308. Back in the early 80's EVERYONE knew that if you bought an untouched LH Torana you wanted the car with the HJ engine as they were far quicker than one with a HQ engine, the later one made the early one feel like a 253 in comparison. The later LH SLR5000 was actually as fast as or faster than a stock L34. Same deal with LX's, people wanted the early cars with the HJ engine, not the choked up HX engine.

Your mate's LX SS must have been a post 6/76 one with ADR27A engine. The early ones were rocket ships compared to any prior GMH product other than a HT-HG GTS350M (if you could keep the diff intact in the LX).

Yes, 308's with single exhaust were gutless, so were 307's with single exhaust. Everyone knows that. Optioning N10 on any of them changed the car dramatically.

HJ auto 308 suffered with TH400 as GMH insisted upon fitting a 2.78 rear axle on most of them. Even a HJ Sandman capable of carrying 750kg optioned with 5.0L and auto got a 2.78 rear axle and single exhaust, no wonder they were gutless. However a HJ GTS coupe or sedan optioned with 5.0L, auto, N10 and 3.36 rear axle drove beautifully. The TH400 is such a beautiful smooth box to use when they are new or in good condition. My HJ Premier is 5.0L, TH400 and LSD 2.78 rear axle with single exhaust. It has only ever been driven for 108,000kM. It is gutless as you'd expect with the factory single exhaust, but the box shifts and drives beautifully. I also owned many HQ and HJ-HZ Statesmans in my time, I used to have them as tow vehicles. I can tell you as a fact the HJ's were the better car, more power and a far better box to both drive and tow with than a HQ Trimatic. Yes, Trimatics improved a lot in the 80's but the HQ box was not as good as a blue/black engine one. The best of the bunch to have was a HZ Statesman (for the way they steered and handled) with a HJ spec engine in it, or something similar as a rebuild.

Edited by user Wednesday, 18 April 2018 12:11:24 PM(UTC)  | Reason: Spelling

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#20 Posted : Wednesday, 18 April 2018 10:26:59 PM(UTC)
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Originally Posted by: HK1837 Go to Quoted Post
Not sure how many times I have to say it. HQ AND HJ 308/5.0L ENGINES ARE NOT THE SAME. HQ 308 engines are HQ engines, end of story. HJ 5.0L engines are HJ 5.0L engines, end of story. A post 8-9/73 HQ 308 is identical in all ways to an earlier HQ 308. All that changed was a LEAN IDLE carby with sealed idle adjustment screws and the aircleaner got a vacuum operated hot air intake off the exhaust manifold stove. The PCV valve was there from way back, all that changed regarding that in 8-9/73 was the PCV intake took air from the aircleaner rather than through the oil filler cap. HJ engines used the same carby as the same HQ engine but got the far better cam and more compression, plus the 25 extra hp and about 10lb-ft as well, plus they kept making power way past where the HQ engine hit the wall - this is all to do with the cam. 1/75 HJ 5.0L carby changed, but only to seal the fuel bowl and vent it into the intake rather than to the atmosphere plus to facilitate a ported vacuum source on all 308 carbs so that the canister would function. Performance was identical to pre 1/75 HJ.

Garbage. HJ cam IS NOT A POLLUTION CAM. It is a Chevrolet general purpose hydraulic cam grind used on just about all SBC design V8 engines of the era (other than the 350/350hp Corvette (hydraulic) and the high performance Z28 or LT1 or similar engines (mechanical cam)), on all engines from compressions of 8.5:1 up to 10.25:1. GMH used the same cam profile on all 308/304 engines from HJ onwards, which included 9.7:1 HJ-HZ, 9.4:1 VB, 9.2:1 WB/VC-VK and 8.5:1 VK-VL, all with the same chambers, all with the same ports. The difference with the Hodlen V8 is they used 1.6:1 rockers, SBC were 1.5:1.

Chevrolet do not have a crappy exhaust port design, the later fuelies have better ports than a Holden V8 did standard. They worked well up to 370hp on an LT1.

That 253/308 development report is comprehensive, either you did not understand it or didn't read it properly.

Not getting into the HP figures again, except to say again you are getting it wrong, Gross figures are the only ones that make sense comparing engines as they are all tested using the same variables.

No BS, total fact. Again end of story. I have the dyno curves for the original 308 tests, IT IS NOT BS - it is fact. GMH raised the HT 308 peak figure to 240hp from about 225hp for advertising. They did it with all HQ engines, and this becomes even more obvious where they re-rate all the engines for HJ, they ALL drop in hp and torque other than the 5.0L which goes up. If the HJ 5.0L engine had remained the same as the HQ 308 it would have been re-rated down to 230hp or just under, just like the HJ 253 was de-rated (it didn't change from HQ). HJ 308 engine IS SUPERIOR to HQ engine, that is 100% fact and that comes from many sources from Engineering docs to road tests, so forgive me if your memory is not trusted on this. EVERYONE who owned a new HJ 5.0L will tell you they were superior to a HQ 308. Back in the early 80's EVERYONE knew that if you bought an untouched LH Torana you wanted the car with the HJ engine as they were far quicker than one with a HQ engine, the later one made the early one feel like a 253 in comparison. The later LH SLR5000 was actually as fast as or faster than a stock L34. Same deal with LX's, people wanted the early cars with the HJ engine, not the choked up HX engine.

Your mate's LX SS must have been a post 6/76 one with ADR27A engine. The early ones were rocket ships compared to any prior GMH product other than a HT-HG GTS350M (if you could keep the diff intact in the LX).

Yes, 308's with single exhaust were gutless, so were 307's with single exhaust. Everyone knows that. Optioning N10 on any of them changed the car dramatically.

HJ auto 308 suffered with TH400 as GMH insisted upon fitting a 2.78 rear axle on most of them. Even a HJ Sandman capable of carrying 750kg optioned with 5.0L and auto got a 2.78 rear axle and single exhaust, no wonder they were gutless. However a HJ GTS coupe or sedan optioned with 5.0L, auto, N10 and 3.36 rear axle drove beautifully. The TH400 is such a beautiful smooth box to use when they are new or in good condition. My HJ Premier is 5.0L, TH400 and LSD 2.78 rear axle with single exhaust. It has only ever been driven for 108,000kM. It is gutless as you'd expect with the factory single exhaust, but the box shifts and drives beautifully. I also owned many HQ and HJ-HZ Statesmans in my time, I used to have them as tow vehicles. I can tell you as a fact the HJ's were the better car, more power and a far better box to both drive and tow with than a HQ Trimatic. Yes, Trimatics improved a lot in the 80's but the HQ box was not as good as a blue/black engine one. The best of the bunch to have was a HZ Statesman (for the way they steered and handled) with a HJ spec engine in it, or something similar as a rebuild.


I never said they were the same but from 9/73 most would say they are the same to look at from the PCV etc most people would see that directly, f me dead I know what they truly are.

You say that the performance is identical but you say that the HJ cam makes more HP.
I say that they do perform the same but for HJ being more willing up top but it counts for f all in reality.

The 9.7 comp in the HJ means f all in reality because when you understand what cams do in reality, then you would know that the dynamic compression is much the same in both, Holden only raised the comp due to how that cam grind works.

I told you that the cam grind is not the same as the chev grind HK to HQ and I know it for a fact very close but not the same at all, I have seen the full specs.
USA had pollution laws before 1972, 1966 I think it started.
What they did with comp on the HJ has nothing to do with making more power at all, Holden had to raise the comp of the HJ so as not to make it loose performance form the early 308 or the the dynamic comp would of dropped a proven fact, the ADR27A comp on has nothing to do with that such at all as it's a new age engine and were not trying to make it match the HJ for power as they were trying to do with the HT-G-Q in the HJ. ADR27 is a Law standard and they were trying to meet it with the help of that cam as well.

The HJ cam is a pollution cam, they could not use a HT-G-Q cam in a ARD27A ever as it will not burn hot in the exhaust as the ARD27A wants.
I think you think that I am saying that the HJ cam is making it loose power, like the ADR27A does, but ADR27A goes beyond that to make it loose power.
Now the SAE HP of the ADR27A is only just that worthless standard that is worthless in reality, a free exhaust test as per SAE would not pump as much exhaust gas back into the engine, so I would think that with a single exhaust would pump more gas in than SAE figures are saying.
HX-Z SAE HP is 161kw = 216hp and VB the same engine is 126kw = 169hp DIN ?

The development report is f all, much more could be said.

SAE HP figures can be made up they are total BS, just look at what you said Holden did for advertising ?
225hp HT-Q and HJ with 250hp ? and you know they performed much the same.
ADR27A everyone knew was just gutless crap and look here HX 216HP ? an you are trying to say HT-G-Q is 225hp ? only a drop of 9hp come on ! and then your saying that the HJ over the HQ is plus 25hp no way ! if the HJ cam was a performance cam it would of been opening the intake earlier and raised the lift, you don't make power by doing what was done, it's done to heat up the exhaust to burn the unburnt fuel off and that's what the cam tuners say it was done in the name of to help with.

I think your mixed up with twin system 308 vs on the Torana's, most 308's had single exhaust

Yes My mates was a ADR27A LX SS.

Yes all 308 pre ADR27A Torana's did go well they were light and had dual exhaust that's why, all had 2.78 diff std but 13in wheels can make a difference as well.

With the HJ on 308 you got single
exhaust and had the TH400 to deal with and this drags a lot of power out compared to a Trimatic, that means less power to the back wheels, to drive a TH400 or TH350 is nice and smooth and all good just plodding about but when it comes to driving them hard they are totally crap slow to change and will not go back to 1st till like 30KM/H factory stock, but one thing with the Trimatic is that you could pick up 1st gear on demand.

Most people claim that the 308 was crap gutless engine and this is because of single crap exhaust and ADR27A came out.
HT-G GTS 308 4SP and Trimatic went real well.

I owned a HG 253 Trimatic nothing was wrong with such at all, but the later ones shift was improved a bit smoother like but that was about it to drive. apart from the T Bar setup was designed by some moron who did not understand the concept of why one would want to use a T Bar for.
At least Ford understood the concept with the fine T Bar setup command and C4 automatic was a joy to use, just magic to use driving it hard and never made you pissed off like the Holdens did or with the TH400 TH350 because they were like I never want to drive another ever again they were shockingly boring and hopeless unwilling to work with your demands.

Sure the HZ Statesman was much better to drive than all before it and a old bloke I worked with back in 1980 had pulled out the 308 because some rings were put in upside down from factory and so he put a brand new 350 chev in his from then on, he said he got the engine from the mob that ran the Camaro at Bathurst and it was one of their spare engines they imported, stock as a rock.

I like the WB Caprice the best and she handled well.

Didn't the LH L34 have HP pistons and more compression, that would account for moving the cam timing as they did to lower the dynamic compression to make it the same as the L31 LH.

Nothing wrong with the 308 exhaust port flow it's only feeding a 308 and with a 253 you put a bigger valve in their you sure do loose power, port it with a 308 to much and you loose power as well I have seen that.
Chev love exhaust port work to perform well. as with the Clevland 4V exhaust port they sure are big but not a great design they like more cam on the exhaust than the intakes, as does the chevs but it's not so with the Holden.
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