Originally Posted by: HK1837 
Originally Posted by: Sandaro Originally Posted by: HK1837 Back in HQ, even dual exhaust and 3.36 rear axle woke them up. A HQ XV2 (SS) with both was basically as quick as a stock manual 308 (single exhaust). If GMH had made them a fraction more special with the 308’s intake and carb it may have changed people’s opinion about 253’s forever. There would have been no point making LH SLR5000 other than the L34 variant.
I think with the 308,in stock trim, Holden made it a low down torque monster. It wasn't a drag strip machine but designed to tow the boat/van.
Fortunately they are easy to wake up and the ones I have built with simple mods, still everyday streetabe, would make the 350 obsolete!!
Probably comes back to the old saying, "there is no substitute for cubic inches"
That’s sort of true for the original 308. From HT through to HQ it was only 9:1 and used a retarded by 5deg 253 cam. Regardless of the BS 240hp advertised power figure quoted, it was 227hp SAE Gross. Compounding this was every 308 powered HT-HQ cane standard with a single exhaust. In LH SLR5000 the dual exhaust were tiny, the combined cross section barely bigger than the Holden’s 2” single.
The HJ engine was 250hp SAE Gross. Courtesy of compression increased to 9.7:1 and a significantly better cam. This engine was a real weapon, just ask anyone who bought a HJ optioned with dual exhaust or, later LH or early LX 5.0L and replaced the tailpipes. This was the highest power rated 5.0L until the HDT engines. The L34 engine was given more
rated hp than the stock HT to HQ 308 (240hp to 227hp) but it was still fitted with the retarded 253 cam, ran the same carby etc. Sure it had larger valves and better headers but without the cam to support it and still having the tiny tailpipes it would have struggled to use that power. On a dyno you’d most likely get it to rev more produce more peak power than the HJ engine, but GMH conservatively rated it. Remember they were trying to hide any involvement in racing!
Must be that Holden put the Torana 1.9L 4cyl mufflers on the 308 SL/R5000 as the pipe going to the muffler must of been the same size ? and going out is the same size as the 4cyl ?
1.9L X2 = 3.8L -VS-5.0L not to mention the V8 does not rev as hard as the 1.9L 4CYL ?
I think it was just cost cutting from Holden. they just turn the muffler over for the right hand side and bend a 4cyl size pipe to suit and both pipes going to the muffler.
Why not just use the 6cly pipes or are they the same as the 4cyl ? i think they maybe, i remember the HQ 6CYL were a real small tail pipe, but for when the Blue 6 cyl WB came out they had a huge, like 2in tail pipe !
I do not see a problem with the size of the pipes to the muffler being a problem but for the mufflers being the real problem of restriction, just as it is so with the HQ-J-X=Z as it's the muffler that is restricted and the main reason for the love of small tail pipes is that so they do not drone.
Not to mention the need for the same size pipe in and out of the muffler maybe that it's not needed after the muffler in regards the car company's opinions ?
Every stock muffler i had seen back in the days were all smaller size tail pipe coming out of a muffler.
Remember how big the original muffler was on a HK-T-G 6CYL sitting along the rear under the boot and the small tail pipe ! I think the V8 of them was a bit bigger tail pipe tho. They were quieter than the Original HD-R were. I remember that note of them and the HK on was not like that. The big deal back in the HK-T-G was that Holden made out how quiet they were ! that was the trend !
HQ 202 exhaust made a diffrent type of note !
The LH 6cyl Torana i do not remember their note but the HQ on were not as quiet car as the HK-T-G in it's body design i am totaly sure of that ! but the LH Torana were not a quiet car body wise you had more noise within the car than a HQ on even ? and this may be why the smaller dual pipes were used or that the Torana was never made for such big pipes ?
I remember the Ford Cortina's from 1973 on and as models progressed, Ford spent a lot of money to try and get rid of noise from a passengers point of view it was not a quiet body design !
A VB on Commodore were a quieter body car than the HQ-Z. The WB Statesman ? more sound deadining was packed into them !
I remember my dads 1976 F100 250 6CYL How much more noise that engine made coming through the fire wall was astounding, you could not hear the exhaust as the tail pipe as 2 miles away down the end but their was a sort of drone hum i would say due to the pipe, as with extractors they also make a noise regardless, it's not a note out the rear tail pipe but you do know that it has extractors on it due to that tingle noise ? That's why Car makers love exhause manifolds ! they rejudce that sort of noise.
