another th350 'Q'

[marq]

Can anyone tell me how much power and abuse a th350 tranny will take?i have visions of putting in a killer 392 and just wondered if i'm going to have to get something else...........Marq

[WildWilly68]

I had a friend who had about 550hp in front of a TH350 and drove it/raced it for years without problems. Mind you the transmission had been built rather well. For a stock tranny with a mild shift improver kit I don't think 350-400hp would be too hard to handle. Most importantly get a good aftermarket tranny cooler, the bigger the better, and use it. Heat is the enemy of any auto trans. Just my .02
Bill

[shifts]

Go with a th400. DAVE

[38Chevy454]

Shifts is right, the T350 is kind of marginal for the high torque of a 392. I used to drag race a 450 hp 454, with fairly high torque. At first I ran a T350, but after breaking it twice i switched to a powerglide. The T350 has a weak link in the intermediate sprag, even the aftermarket part that is supposed to be stronger than the stock one.

A T400 is hard to beat for strength, I would recommend it over a T350 for behind your 392

[marq]

will a th 400 fit staright in and is it the same shape as the th350?

[38Chevy454]

T400 is a bit bigger around and longer by a few inches, assuming short tail vs short tail. It should fit anywhere a T350 is without any significant troubles. Cooler lines are approx the same as is the shifter location on the side. Vacuum modulator is different, T350 is at rear and T400 is on side.

The T400 uses a different spline output shaft than the T350, so you need a different yoke.

[cabriolethiboy]

Seems like I remember from my old GM engineering days(we made trans solenoids) that the 350 in TH350 means that it was made to withstand 350 ft/lbs of torque(with a safety factor ofcourse). TH400-400 lbs/ft of torque. The numbers changed after that to mean something else. 700R4 does not mean 700 lbs/ft of torque. If there is someone that works at GM Hydramatic they could say for sure.