23 to 18 spline what it takes and how good i'll be!
The 23 spline is a very strong unit, but anything over 500 hp or with slicks and I'd go straight to an 18 spline. Once Mopar Muscle was down the road at the local hotrod shop doing a feature on a Hemi Dart they built. Everyone got into the swing of things, and they pulled out a '71 440 'cuda that had just been restored. They did a burner in the driveway with it, and the 23-spline failed right in front of the Mopar Muscle guys. They twisted the input splines nearly a quarter of the way around the shaft. Fortunately the had a new 23-spline in the 'cuda, and it was back in action before the photo session was done.
23-splines are plenty strong, but you have to be realistic.
I might have a explain'ation for some of this. I have built a lot of tranny's for muscle car guy's before I retired my shop for health reasons. Other than M21 M22 Muncies with the bellhousing face machined out of square with the main shaft. 34 to be axact. This happened to 2-833's and 1-T10bent bolt mounting ear.
I found out what happened on the second 833 23spline in a 383 Ply. I rebuilt one for a kid and he broke it doing a burnout like above.
TWICE! I did it for him free an I thought it was something I did. So after the second time I went with him on the test drive. Remember, 383 B body
3.55 gear bias ply tires. I said OK, Do a burn-out. Thank god I noticed he was in 3rd GEAR! He would get all exited and was in 3rd not first. With that tall gear and a swept off rock seal coated street he would of broke a truck tranny. Found out that is what happened to the others.He was always first to mouth off that 833's were junk. Exited and in the wrong gear. That is the only way I have seen a 23spline break in 36yrs that was not wore out, bad bearing, low oil, contaminated oil or out off alighnment. If any bellhouseing retainer hole is out of center .008 you will break tranny's. Not square to the crank or main shaft, you will break tranny's.
Most breakage I have seen was because of miss-alignment. Not, this tranny was weak ect. Someone here said the USA muscle car tranny's were about bomb proof. he was spot on. If you are breaking 23spline 833's on a regular basis, you have something out of alighnment. I have only ran into a very small handfull of guy's that know how to dial indicate in a bellhousing. Yes, you need to do it to stock ones too. More are off than scattershields.
No where in these how tough is this tranny posts is alighment mentioned.
This is why I posted in this old string, because it has some great info and some bad. If everything is set up right I find it hard to swallow that a 23spline will break in under 3500lb car with pump gas and reasonable cubic inches. that being 500. I have also seen guy's run 2.76-3.23 gears and slicks, launch at 5000rpm and blame the tranny!
Thank You guy's for such a great forum with so much great advice.
Take care all,
Rick