Originally Posted by: HK1837 ![Go to Quoted Post Go to Quoted Post](/Forum/Themes/soclean/icon_latest_reply.gif)
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.