ok guys i'm swaping a TH350 into my 1991 firebird.. now this isn't a "how do i swap a TH350 into my car" thing... i already have a TH350 but i want to rebuild it... i can do a stock rebuilt with no problem BUT this transmisison is goign to be behide a 550HP small block with a 5000 stall 8" convertor this car i HOPE will be in the low 12's to high 11's i know the weak points in the 700R4 but so far the onlything i can find is that the TH350 has a weak sprngs... btu what else ? i want to built this tranmission with a rev. manual vavle body and a transmission brake so does anyoen know of a web site that has some good info on the TH350 on how to make them stronger?

 

anyone?

 

The sprag is weak and some other parts are weak; this should answer all your questions (it's a list of 350 and 400 parts)
http://www.400raptor.com/