Originally Posted by: HK1837 There is absolutely NO WAY that an M21 with a 3.08 rear axle and 14" tyres is the best combination in a Holden. It simply is not or GMH would have done it. In US performance vehicles and followed suit by GMH with the GTS327 and GTS350 the M21 car got 3.36 with 14" tyres and 3.73 with 15" tyres (approx. same effective ratio). 3.08 is WAY too tall for an effective 1st gear with an M21 and 14" tyres, and would never be seen as a performance vehicle. Once the XU1 took over than mantle, they did change the GTS350 manuals back to 3.08. There is no way you could idle any of the Holden 308's off the mark with an M21 and 3.08 rear axle with original ER70H14 tyres, not even the highest power late 1974 to mid-1976 version would do that without stalling.. Whack 5 people in a sedan or stick 500-700kg in the back of a ute and you'd not even be able to reverse up a driveway without destroying clutch - it is hard enough with a 3.36 rear axle!. I had a HZ Kingswood L31 M21 sedan that had been changed to a 3.08 rear axle and it was a pig to drive, you had to burn clutch to take off. Even with the engine rebuilt to similar power and torque figures as a HJ engine it was still not an easy car to drive around town. As far as autos are concerned I always liked Trimatic with 3.08 and 14" tyres, even on a 6cyl tonner. My HJ Premier with L31, TH400 and 2.78 rear axle with 14" tyres is a nice combination as a cruiser, but it is never going to be a performance vehicle with that diff ratio.
IIRC dual exhaust was not standard on a HZ L31 unless it was a GTS, even then only clearly available on V8 Kingswood sedan and Premier sedan (there is some confusion regarding N10 on wagon and Statesman as documentation is contradictory).
The standard V8 valve bounce at 5000RPM in top gear you can get 5500RPM out of them in other gears but I must be because of the time spent at such revs the springs go wonky.
So that was 5000RPM at 200KM/H I found with my Sandman and SL/R 5000 that I had to back off because the stock engine would valve bounce, both had 3.08 diff and 14in wheels.
185KM/H would be top speed with a 3.36 and 165KM/H with a 3.50 ratio, a mate had a stock 202 but for twin carbys LH G Pack Torana 3.50 ratio 14in wheels and it valve bounced at 165KM/H.
Both my stock 308's had extractors and good free twin exhaust and free air filter and this makes a big difference to how they come from the dealer floor, and I am sure off idle they will take off if you dropped the clutch out directly.
I put a 2.78 ratio in the SL/R5000 when I snapped an axle and yep 1st gear was a bit to high and it would of stalled I am sure by dropping the clutch out then, but she had that much torque it was not a problem to drive anywhere.
I have reversed enough trailers on shitty job sites and stupid drive ways in 43 working years and yes the M21 reverse is bloody high but their is a trick to working the clutch the right way to make it much better, you never rev it up high, I use the lowest rev I can to get it rolling off the mark and if it stalls near the top of the drive way that's it, I just start shovelling out the sand of the trailer from their, it maybe a fast reverse but if you
have confidence in you trailer it can be done, with a bad trailer that jack knifes like a bastard no way.
But that VY SS ute I had, 1st and reverse were bloody high and I would fill it with sand and bags of cement once a week and never buggered the clutch up because of it, it did bugger up at 100,000KM but that was a fault they had fixed in the VZ but I did put a heavy duty AEC ? stage 3 In it then but the peddle was heavy due to that and that had did 130,000KM when I sold it. did a lot of city work in traffic and just would idle and let the clutch out a bit and she would move along, I remember doing about 6KM of that due to a smash, when I got to it 3 dills have just had a slight nose to tail shunt but just sat on the bloody road, I was pissed off and got up them to move ya f ing cars of the f ing highway for f sake you pack off c---so
Yep your HJ Premier would be a good cruiser with 2.78 ratio for sure.
I like the 5.8L ZH Fairlanes for long trips they had the 2.75 ratio a mate had one and sitting in the back drinking was a pleasure to eat up the km as was his WB Statesman Caprice.
I remember tossing my cookies in the marquis
once, bloody electric power window did not work.