No, 226hp gross. None of this is speculation. It is all hard found and researched facts by a number of people.

Dr Terry is spot on with his figures and he is using the same sources as me. The 175hp@4800 and 240lbft@3000 is spot on for the export HX-HZ 4.2L engine - it is the identical engine as installed in HQ and in HJ's complianced in 1974. As I said GMH RE-RATED their engines in 1975, it is a simple fact. We think they did it in line with LX and probably as to soften the blow for ADR27A coming in the middle of 1976. The 3.3 was give 110hp@4000 and 190lbft@1600. Same engine as HQ and same engine as in earlier HJ up until late 1975 when they re-rated them.

Ignore Max Ellery books - they are full of such errors.

I give up, I can only give the facts and that is it. HJ is a bigger cam used for the 308, not the earlier compromise and retarded 253 cam. END OF STORY! It had zero to do with ADR27A.

The performance of the GTS350 has nothing to do with the driver. The same drivers drove them and found the real story with the properly tuned HG's. AMC simply proved they were correct. I'd trust their words in 1971 more than speculation today.

GMH did not need to do anything to the GTS350 to win in 1970. The GT-HO performed better in both total race time and lap speed in 1969 than the Phase II did in 1970 and in 1969 still got beaten by Monaros driven easily on road tyres. If you need any more proof of the right way to drive the GT-HO look no further than Bruce McPhee's effort in 1969. If GMH had used HG in 1970 then they'd have another 12 months of development versus a new untested PhaseII. 1971 with the PhaseIII would have probably been another story with an extra 12 months of Cleveland development, but by then the HG GTS350 was dead by at least 6 months and the 1971 L48 (as fitted to HQ) was never going to perform like the 1969-70 L48. GMH did play with putting the 1070 LT1 370hp 350 into Old Man Emu for 1970, complete with M22 and 12 bolt - no GT-HO would ever have seen which way that car went. However it was canned by GMH due to cost and due to the fact that those engines would be no-more in US vehicles by July 1970 (the end of 1970 model year production). As it was they had to turn to the Canadian engine plant for the final manual 1969-70 spec L48 engines to see HG GTS350 through to the end of 1970. There was never going to be a high performance HQ GTS350 after the original HK based HQ was canned a few years earlier. The L48 engine as fitted to HQ GTS350 is the identical specification engine to HT-HG GTS350 L48 (manual) engines, it is just the 1971 version of it, just like the dog ADR27A 253 and 308 engines are the 1976 versions of the prior year engines, same L32 and L31 option codes. There was no other 350 4barrel 350 engine available for HQ other than the Z28 Camaro engine, which was lower performance than the L48 engine that was in HT-HG.

A HK GTS327 or HT GTS350M is nothing like a GT. They are far superior in performance than the respective GT it was sold against. Only the GT-HO was a competitor. Ask any stock GT owner that tells the truth what happened to them at traffic light derbies in the late 60's and into 1970 when they pulled up against any GTS350M. Same with drag strips of the day. Same even with a GT-HO owner when left for dead to 70mph by a GTS350M. As I've said before Dave Bennett managed a 15.6@89mph quarter and 0-100mph in 20.8s out of his brand new GTS327 (3.08 rear axle). He took it to Calder when it was 10 days old, fitted with by then a 3.36 rear axle. Dead stock car, running the GMH supplied D70 Dunlops, all he did was dropped the exhaust behind the resonators and managed a 14.46s with a near empty tank. That is not a slow car. This is not unique, Rob Luck reports in Racing Car News in September 1968, a 3.36 rear axle GTS 327 - 0-100mph in 19.8s, 128.5mph top speed (all on corrected speedo). 15.4s quarter at 92mph. These figures are HK GTS327 with a 250hp engine. The GTS350 engine with the same basic car with a true extra 50hp was no way as slow as the cars GMH supplied for press tests. These are simple, easily researched facts, not myths and BS perpetuated over the years mainly by Ford owners or people thinking with blinkers on. All you have to do is look at how the NHRA rate the L48 engines in the USA, and you can see quite clearly they are very effective power producers. Sure the Clevelands had an extra 30hp, but as you've pointed out clearly that extra peak power doesn't not always equate to a faster car until you get up to truly high speeds, and at those speeds on Aussie Roads of 1969-70 the car's dynamics become just as important as 10% more power.

Edited by user Sunday, 5 March 2017 3:02:10 PM(UTC)  | Reason: Not specified

Don't know, but there is zero doubt that they are SAE Gross. It is documented in internal GMH Engineering documents, first changed in 4/75 but starts to appear in Owner's Manuals around October. GMH didn't go to net until DIN figures in VB. They may have got a new dyno? Who knows until the internal docs explaining why they did it turn up. But the fact remains, when they were re-rated they all dropped, some significantly except the 5.0L which went up.

Correct, HX 4.2L cam is a new cam. No-one ever said it was retarded.

Yes a driver has input, but the key is Mel Nichols and Rob Luck both tested the nobbled GMH Press test HT's and then HG's that were not fiddled with. Same car, different ornaments on it. AMC simply replicated what these guys discovered to prove beyond doubt that what was reported by them was real. You can doubt it all you want, the facts are there in black and white. Go find the magazines and read them, not listen to old wive's tales handed down over the ages.

Engine wise true, but the HT-HG GTS350 in proper tune was that close to a PhaseIII (using magazine figures for the PhaseIII) in 1/4 mile and 0-100mph times that it really didn't matter. So an LT1 370hp engine or even the Corvette L46 350hp 350 would make it a no contest as a vehicle comparison. Assuming a Monaro equipped with one of these would last the 500 miles I cannot see how one of the Falcons could have beaten it using the race time and fastest lap data from 1970 and 1971. The only real shame is it never happened. Chevrolet pulled the trigger early on the 1972 mandatory emissions spec engines, and went whole hog from July 1970 for 1971 models. Others like Pontiac, Ford etc waited until the last minute. If Chevrolet had continued with the high output engines until 1972 models (7/71) we may have seen a HQ with an LT1! In the end though GMH didn't build race cars (not officially anyway). Ford was the opposite, it was win at all costs. So it is unlikely that the LT1 engine was ever going to see the light of day in a Holden.

I know exactly how camshafts work, and even moreso how manufacturers try to economise using as few different camshafts as possible which is what GMH initially tried to do with the 253's cam in the 308. The reason the HJ 5.0L was made so much more powerful than the HQ 308 using both cam and compression was because they had to have a far more powerful and torquey engine for the Caprice than the old HQ 308. The HV and its eventual replacement the HJ was supposed to have a 400ci engine but GMH further developed their own 5.0L engine to work almost as well, and thus have a huge cost savings on the car with no need to use an imported engine and to have far more expensive radiator, power steering bracketry etc as they could use all the same stuff the 308 had in other HJ. That 400ci LF6 engine they had here fitted to various HQ was SAE Gross rated at 255hp@4400, and 390lbft@2400 or if you like DIN 170hp@3400 and 325lbft@2000. Compared to the HJ's 250hp@5000 and 320lbft@3400 SAE gross, you can see why they decided to do it. The cost savings would have been over $500 per car. The 400 disappears from HJ plans late in 1973 and there is a revision of the HJ features manual that says so.

I'm the same, stating facts without prejudice! Everything I have typed is factual, if not it will have qualifications like afaik. Or use wording like "I cannot see". Everything is backed up by GMH facts, text from magazine reporting of the day or other such input. None of it is speculation or based upon memory, and if it is I'll say so. The documentation all of it is quoted from is in my possession, and I've been collecting it for years. So there is no need to doubt the facts presented, regardless of whether the facts contradict long standing beliefs.

Agree, the TH400 did rob power and I've never been sure which came first - the chicken or the egg. Was the TH400 added due to more power, or was more power required to operate it? I suspect the higher output 308 exceeded the torque and power limit of the Trimatic of the day which triggered a stronger box. GM did this regularly, they'd leave a weaker box in place behind a more powerful engine (like the Saginaw behind the 375hp 327) but fit a Muncie to the 275hp 1969 LM1 350 (our GTS350 auto engine) or 270hp 1971 L48 (as in our HQ). They key is the torque figure. The 1971 L48 had 360lbft , LM1 365lbft and the 327/275 had 355lbft. The tipping point was obviously between 355 and 360lbft on the same size car. The Trimatic to TH400 tipping point may well been between the HQ 308 and the HJ 308, but in the lighter Torana not deemed an issue.

The cam duration mentioned would depend on the exhaust system in the end. More exhaust duration on closing can help with a restrictive exhaust. If I remember my cam maths properly you'd get increased low rpm torque with the earlier closing at the expense of peak power.

Are you sure the HQ Monaro was a 253? I thought it was a 6cyl. Originally anyway.

The Torana had to use the Tri to fit.
The T400 was used in the powerhouse HX etc.
I think that the Saginaw was the only box at the time with that 327.
The Tri-matic was found out to bugger up due to using reverse up steep driveways as the friction plate material was changed to fix that problem as far as I know that was the main problem, a old dude I know with a 3.3L UC Torana had a real steep driveway and his buggered up as well, so I think it likely is true, not to mention they did get improved as the years went by.

The extra duration on the exhaust helps with a bad exhaust port flow, you don't need that with pre EFI 308's, as for a restrictive exhaust system nothing helps that.
Dynamic compression will go up.
You should get more torque and power all over.

I think it was in fact a 173 with 3 on the tree, now that you mention it.
I think one of the twin exhaust was just hanging their, I will have to investigate that.
When The Night Rider hit the brakes at the point that the cops tried to shoot him at the intersection, see it was a EJ peddle box that's shown, not a HQ type of one.

Edited by user Monday, 6 March 2017 7:50:14 PM(UTC)  | Reason: Not specified

1 I agree.
2 I am not a fan of them GM boxes but as too such, some were straight cut gears if I remember correctly. GMH would of done the bean counters and all and the 10 bolt got the go ahead.
3 Well no where as good as Fords C4 auto, the Holden T Bar was stupidly set up by some clown who needed a kick up the arse, the Ford T Bar setup was magic and the C4 auto was magic too use as it did everything just right, the Tri-matic would drop back into 1st at any speed and that's not good at all for the poor auto.
4 Holden just wanted to keep the same dynamic compression mainly with the 308 HJ cam or would of lost power, they had too do it.
Look at the Holden 202 low comp and high and the auto and manual trans get a different cam, the low comp loose power and torque everywhere and the manual 202 gets the smaller cam and the auto gets the bigger cam, the comp stays the same but they must of worked out they wanted more power for the auto, but them 2 cams are not as different as the 308 HQ or HJ is.
VB 3.3L
Manual 9.2:1 64KW at 3600 / 217NM at 2100
Auto 9.2:1 69KW at 3800 / 205NM at 2200
Low comp 7.5:1 55KW at 3200 / 195NM at 2000

The bigger the cam be it duration timing or even lift can order a increase in static compression, so the same dynamic is kept in line ball with what they are happy with, Holden does not increase comp for nothing.
How that duration timing, lift and centreline angle all comes into play with what compression is best needed to be.

Look at the low 7.5:1 vs 9.2:1 that has to do with the fuel, it's running on Standard and if you want to or have to run Standard in the 9.2:1 you will have to retard your timing to save the engine being destroyed and by doing that you will then loose more power and fuel economy than the low comp engine, so that's why they made the low comp engine for, the same thing with most idiots bombing up there cars were going to high comp and destroying the engine because the Super fuel was not good enough for that compression, it's best to drop the compression down a bit lower than it is to go too high, it's best to talk to a cam doctor and work out what you are truly looking for out of an engine, the cam is the main thing to get just right with the whole setup working with the heads breathing and compression for the fuel you have and then you have the correct type of intake and exhaust.

Most fools think a bigger cam is the answer to everything, bigger carby higher compression bigger ports and valves it's not always a fact. but that is bloody hard to inform people about, we had a dude that built hot engines in the 80's his name was Grenade and drag racing was his game. but one has to find one that can build great street engines that do last and do a better job, it's not all about the max HP crap, old Grenade thought nothing of rebuilding some dudes engine every 3 months, does not everyone do that ? yes drag people may do but not on a street car, unless your a drug dealer trying to get rid of money.

Looking into all this, I would say that all the commodores from VB on would have to be correct power ratings but for some reason a few are not correct.
One being the VS series 3 with 179KW because of the crap single exhaust verse the much better flowing twin on the VT 179KW.

2/ You say that the VA prefix VK has 177KW, but this has 117KW in fact in 60 years of Holden book.

3/ 134,234,334 packs had 177KW on paper with manual box, with big valves ? I thought that the 177KW was a small valve engine with just a bigger cam. the 184KW is the same engine and cam as the 177KW but only bigger valves.

As for the EFI 5.0L 165KW 180-185KW yep they did go much like the pre ADR27A 308's with twin exhaust, but EFI with a little less torque right down low and went a bit better up top.

My stock 179KW did not have the torque of my HQ 308 down low, if say I was too say stand out side the car and start the car accidently in gear I am sure it would go straight through a brick wall, but not the 179KW one and as for that low down torque the new Gen 3 in the VT had no torque down low at all, it was just totally hopeless till you hit 4000RPM, I tested drove all the new VU Commodores around the Norwell test track and I was happy bought a new 5.0L 179KW and kept that till the VY came out, lucky the VY SS had much more torque down low and I could live with that, the GEN 3 does not have the grunt down low like a HT-G-Q 350 Chev did.