not disagreeing with any of that but a comment -
I can't work out and no-one at GMH could tell me why... the 253 was hobbled from the start with the ridiculous 2bbl/intake combo that was fitted. No performance !
plus ridiculous fuel usage was the result

Best and easiest hipo upgrade for a 253 is to put a 4bbl dual plane manifold (anything factory is ok) with a suitably jetted Quaddie.. things even use less fuel
when you do that.

The 253 V8 responded well to a single 2 1/4 free flow system or as the HQ SS dual system.
If we were to look at Net power figures we would see the reality of the torque curve and HP in reality, fitting a 4BBL on a stock 253 single exhaust would be f all difference.
It's the open system and a small Holly 350 2 BBL improves them, or a 480 CFM 4 BBL I think they are does well.
One mate had a worked 253 I think it had a 600 Holy and it did 7000rmp in 3rd gear, yes it went well but totally lacked the torque of the 308's.

I have driven a mates stock HQ 308 with stock like dual exhaust and a 2BBL Stromberg on it, went surprisingly well but for top end lacking somewhat, but still cruised at 180KM/H no problem and could do 195km/h it had 3.08 diff. Old mate would sit on 180km/h cruising late at night coming home from Bundaberg heading south. one time the cops were out sitting side of road with radar and old Peat just put the foot down flat and the carby noise started to growl.
The Torque was still their in the 308 with 2BBL Stromberg. I was doing burnouts in it and all.

I do not see any fuel economy issues with the 2BBL Stromberg.
I found the 308 better on fuel economy than the 253 at speeds over 160km/h, you could cruse at 180 with a 308 and the 253 would be flat out.
Same with the 202 The 253 is better on fuel on or over 140km/h easy.

What mods ?
The 253 needs 2 1/4 free flow or dual that was in the SS and that's the key to making them perform well or fine and the rest is just f all with a stock engine.

308's however it's all about the freer exhaust to make it perform best, oh and the air filter and then it's about the Jetting.
You need at least what was the dual HQ system for a start with a 308 or it's a total shit box of an engine, that so many complain about the 308 being so gutless.
When I got my first 308 it had dual 2in system with extractors, then I went dual 2 1/4 real free flow and loud as and it improved even more. Copes got me and all the exhaust shops ranted like you would not believe that a single 2 1/2 will make much more power than what I had, well f ing bull shit ! that killed it's performance hugely.

As to the EFI 5.0L I have seen extractors and free flow 3in and big cat go backwards in fact in performance, proven with a mate and my car stock hosed it off, but once he got it chipped it blew mine into the weeds. I am talking 3rd gear trials, so it's clear fact.
So jetting can come into it.

Just remember that a 2BBL carby CFM is not based of the same readings foundations as a 4BBL CFM. so a 2 BBL with 350CFM and a 4BBL if it was rated at 350CFM would not feed the engine as well as a 350CFM 2BBL.

When people make claims of the ZC Fairlane with 351w having a 4BBL carby and standing in awe about such, well it's only a 480CFM.

Not to mention that the 307 HK 2BBL CFM is bigger than a 2BBL Stromberg's CFM.

look at the XB 2V 302 and 2V 351 they have 351CFM 2BBL carby. so I doubt that the 480CFM 4BBL is truly any bigger really.

Simple maths yes but then again their is more to it, as to the flow of the carby fed V8 heads the 253 flow real well on the exhaust, so you do not make the valve bigger or you will loose performance on a stock 253. So different story with the 308 on that point and this makes a bit of difference, so even if you worked out the flow rating to equal what is best with a 253 to a 308 you still have that difference, the 308 regardless loves to be un restricted but the 253 not so much so.
Just like with chev V8 the exhaust ports are not designed as well as the Holden and the 302 Windsor heads exhaust ports at the time are shit compared with a Holden. That's why they put Cleveland heads on Windsor 302 and even the Cleveland heads exhaust are shit designed to a Holden.

If we want to talk about EFI 5.0L heads well if they did have a 4.2L EFI they would have to use different heads, as the EFI heads flow to much for a 4.2L to perform best in a stock form. they would of had to make smaller ports and smaller valves, to make the 253 perform from right down in the rev range and up.

Most people only talk about max HP but such talk is just shit tossing on and nothing to do with practical reality over all.

I remember that the 307 2BBL is a bigger CFM than the 253 Stromberg. I think the 253 is about 280CFM and the other around 320CFM I think of the top. I have it written down some were.

As to your point about any intake on HT to VK is total BS, one should look out for crap intakes that flow to much, I have seen such with a open,that's not a two plain, being total shit on a worked 308 only a moron would use such on a street driven car.
You try and get away with the smallest intake system that you can get away with and never something that's to big on a street driven car. a little smaller is better than too big. because it's not all about top end.

If you look to 2 stroke MX bikes before reed valves and then come the 1975 with the Suzuki RM125n to the RM125s it's clear, big ports are shit, yes the power up top is their but with the RM125a and RM125b if you have ever ridden them you can see why chasing max HP was just shit in reality, so with the B we got more performance through the range that made better times and much easy to ride than a S.
Nowadays people would not have the balls to ride an S because it was so savage, you had all out power or nothing, it was like riding a scrub bull.

Drive a XW GT-HO same thing and then they tamed that down with the XY GT-HO by using a smaller lift camshaft and the XA GT-HO was going to have a smaller camshaft grind again and able to run a 3.0:1 diff. You can not run a XW or XY GT-HO Camshaft with 3.0:1 diff. you can hardly drive a GT-HO P2 P3 on the street for a start, A grandmother could not even get such off the line and if she did maybe wrap it around a tree.

So it's not all about the bigger intake or bigger valves or most compression or biggest exhaust at all or 0.060 over bore, that crap is for wood ducks.

If I were to build a healthy like near stock 202 from when we only had unleaded 91 octane or when 95 got too expensive for most people, the highest compression you could run would be about 8.8:1 max. with the stock cam 8.6:1 max to be safe.

Do you think the 4.2L V8 would of been a better option than the V6 ?

Well I never liked the VN-P-R V6 due to it being a chaffcutter, but then again it was a good performing thing. not to mention it too on the role of the 6 cyl market.

After the Holden 202 being the number one selling Holden and then we got the 3.0L for the call and then the V6 3.6L took that on and Holden explained all that being a better option on fuel ect ect, so the 4.2L V8 would not of cut that call, yes the 3.9L and 4.0L Falcon is about, but we know that they use more fuel than the V6.

Sure.

I owned both a new XG Falcon ute 4.0L and the first VS V6 at the same time both 5sp and I liked the XG much better than the VS V6 to drive over all, tho I liked the interior of the VS as she had more room but the seats were shit in the 1st VS, the 3.8L was better on fuel. but the XG handled far better than the VS as the VS was totally shit understeering pig and then would snap into a wild oversteer, just totally spastic handling car. The XG never understeered at all and was controllable oversteer and the shocks were ok, but the VS was shit shocks, so I had to do all the springs and shocks and put 1.6 deg neg camber to transform the car so I could drive it, Ok the VS brakes were good but the XG were shit due to fade, crap pads.
Then I got a new V8 VS 179KW 5sp and well I had to do the suspension again but with 1.4 neg camber all was fine, but as for the 5.0L such is a far better thing to drive than the 3.6L or 4.0L. but I had to run it on 95 octane on hot days of if I got up it, but them days 95 was only 2c more a litre.

I was impressed by the performance of the 4.0L and 3.6L in the day, as you needed a good stock 5.8L to keep with them performance wise hooking in. not to mention the XG could do 210KM/H speed limited mine was, and the 3.6L could do 218KM/H both manual and auto. when the Falcon ED came out they were all speed limited to 180KM/H, so them XG built from the ED on are 180KM/H limited as well.

I do not like the roller camshafts in that they lack real low down torque off the line over a flat bottom lifter does, 500rpm to 1000rpm I believe.

The 5.7L Gen 3 have plastic lifter buckets and they are shit as they can crack and also the lifter shags them out and then you have a shagged camshaft and then the rest of the engine is shagged as well. not to mention all the problems people had had with roller lifters Ford Windsor V8, not with the Holden V6 that I know of.

The SER 2 VS V6 got the getrag 5sp box and I think they had a lower 1st gear.

I got a new VY SS 6sp ute in Jun 2003, built in June as well. I did not tow with it, yep 1st gear is very high on them and the clutch was very grabby from new but that got or worked better later on. my builder mate got a VY SS 6sp ute in Dec 2002 I think and towed a huge trailer and he put a 3.9:1 diff in it and he was happy with that ratio. then he bought a VZ SS 6sp ute Dec 2004 built and thought because the VZ SS 6sp sedan's got the 2.73:1 diff, that the SS 6sp ute came with the 3.73:1 as well, but they did not ! The VZ SS 6sp came with the high 3.46:1 and he went ballistic ! What the f ing hell did they do such to the ute pulling his hair out, It's the ute that needs the lower gearing if any thing, so he thought that he could of got away with the 3.73:1 gearing but he had to change the ratio now, so he went for the 3.9:1 again.

Costco fuel is Caltex, Well I never use Caltex petrol as I found out it's shit. It took me a few years to find this out but I worked it out and proved it. I can hear when a car runs on such fuel, now I can pick up on it as their is a distinctive noise when you are up it, not to mention the smell is rotten eggs. over the last few years it has gotten better than what it once was. The Caltex E10 94 is ok but 91, 95, 98 are what I avoid.
I run Shell E10 94 In my car and 95 is the best performing by far but to expensive, so 94 E10 has to do as it's fine, 98 Octane I thought would be the best but it's clearly not in my car. and it has a 10.5:1 compression ratio. it says to run 91 in it but come on ! no way ! the performance on 91 is shit. They only put that crap about running 91 so they can sell the cars, because no one wants to fork out for 95. not to mention new cars from say 1995 on were not designed to run on 91, they can because the computer retards the spark timing, but that undermines your performance and economy.

That 1996 VS V6 auto my wife had would always ping on Caltex 91, I would got to over take on the highway and it would kick back to 2ed and rattle rattle instantly and then disappear and rattle from 5000rpm to 5500 every time for years, as she used Caltex fuel, but I would fill it up with Shell 91 or BP and then never ever a ping ever.

That other noise that I hear with Caltex is maybe an ping but one that has not quite become a ping that people can clearly hear. it sounds like a muffled burbling noise, but you have to have an ear for it to pick it up. it took me years to detect such, but I thought that petrol was all the same before hand.

My VS V6 could not go over 205KM/H on 91 Caltex but would do 218KM/H on BP or Shell 91.

What is the lowest diff ratio in a EA on be it a 4sp auto or 5sp manual Ford 3,23 diff ratios or in the case of mine a HD 3.27 in the XG.

So it's has to do with how fast that tail shaft is spinning and is it up to it ?

Well a XF 4.1L may of ran a 3.23 2.92 2.77 2,53 ?

So with the EA 3.9L 5sp they could do 215KM/H with a 2.92 or was it a 3.08 about some time after then. so that speed with such a shaft is what we is looking at, is it up to it ?
Well mine did a lot of work on the limiter 210KM/H and I even asked why at the dealer and they did not have a clue at all that they were speed limited, they thought it was the fuel filter full of crap ?
I never had a problem with the shaft at all in 2 years and over 100.000km

Sure the Commodores all have 2 shorter shafts. and the longer the shaft adds to flex and the digger diameter should be better strength at high speed, some of them Fords did get a alloy shaft that was wider in XR6 and XR8 utes and they were speed limited higher. 230KM/H I think max.
So it must of had to do with cheap product values as to why the 180KM/H limited.

Now a mate of mine bought a XG ute after he seen how good mine went, put his order in that day for a new one. but his was speed limited to 180 and he went off his rocker and got it removed, under warranty they replace his tail shaft but they found his recite that the limiter was removed in the glove box and charged him for the shaft. but the reason why the shaft was buggered he said, was from him doing figure 8's out front his work showing off to the boys. after that she got the vibration he said.
Now his XG engine was smoother then mine as it was made when the ED Falcon came out and they have a better crankshaft I believe, so the XG from then on must of got that crankshaft as well.

Now my VY SS 6SP was speed limited as well to 210KM/H and I had that removed and had no problems at all and I had it up to 255KM/H.
That mate of min with his VY SS 6sp ute with 3.9:1 diff would drive up to 275KM/H as his was supped up as well and he flogged out the rubbers in the shaft ends. now I do not believe that he could get it out to 275KM/H maybe the speedo said that ? but from 210KM/H on my stock could flog his SS easy as, and he would just back off in the end and give up trying as we hit a straight. I worked it out that his gearing in 5th was too low to take me on from 210 and his 6th was far to high to do anything.

Shear genuis !!

Reminds of a story from many years ago. A friend of mine had a workshop a few suburbs from ours.

He fitted a very expensive "performance" clutch kit to an early Brock Commodore. He completed the job and the customer picked up the car on Friday afternoon. He returned on Monday morning, very unhappy wanting a new clutch under warranty.

What the customer should've done was to remove his drag racing time cards from the centre console. Woops !!

Dr Terry

Broke a rear uni ? what rev would the tailshaft be doing at 180KM/H I wonder 2.92 diff and 14in wheels or 15in.
I can not believe that the uni could be the problem. unless it was worn out.

How could a tailshaft that lets go at the rear be the problem digging in.

I thought that the tailshaft bend in the middle because the forces their are the longest and the shaft gets a wobble up, maybe more heat over the distance driven as well and a bump in the road sets it off, but one should know that something is up beforehand with a vibration before hand. maybe it was compromised before hand doing drag racing burnouts etc abuse.

I have seen tailshaft busted in a mates brothers stock 173 HQ Holden 3 sp manual, back in 1980 he would go out on a big hill and let it roll back a bit and then into it. so even a gutless 173 can hammer a tailshaft if abused. yep bent in the middle and twisted.

Now I had a problem back in 1982 with my stock 202 HQ 3sp manual, I had just bought it 64.000 miles up and went to Brisbane from Bundaberg and the bastard vibration from the tailshaft was shocking it had been RACQ tested and I seen him grab the shaft so all good front and back uni's so I had to sit over 90mph as then she was smooth as, the vibration cut out 90 to 100mph. down and back.
Got home and tried to pull the shaft out and no way ! the Yoke would not come out, so I got a car and pulled it out with that ? looked it over and pulled the front uni out all fine only dry and rusty, so in with a new uni and bit of oil down the spline of the yoke and all good.

Another thing is if one pulls out the tailshaft you should mark it and put it back in the way it came out, as sometimes you can have a shaft that vibrates and turning it about can stop the vibration, so what if a clown pules out a shaft ? and pays little attention to what they doing does up the U bolts wrong too much torque or not enough on the nuts, just do up one side of the U bolt real smart or the shaft has been out a number of times and the U bolts are flogged out and some have a tag that you bend over so if the nut were to go loose, has been tossed, so what ever ? I have seen people who cut corners with many things that it's f ing shocking. That's why I never let anyone touch my cars ever.