1979 Trans AM 6.6/ TH350 or TH400??

Hello, just needed some help. My brother bought a 79 TA 6.6L with an auto matic but needs a new tranny. He doest know whether its an TH350 or TH 400. He says he has a 350 lined up to buy from a guy at work. I just wanted to know if you guys knew? I appreciate your guys' time. He tells me that the 400s are longer than the 350s. Anywho hope I gave enough Info.

John

'79's came with TH350's. The last T/A's with TH400's would have been the '74 455SD. The TH350 will be plenty strong for that engine, especially if it is the Olds 403 (6.6L). The 403 is a small block that isn't suited for HIGH HP due to the windowed main webs. Figure on getting about 450HP MAX out of it before things start to break.

cool thank you for the info, greatly appreciate it!!

What Morely says is correct, but ALL '74 T/As got TH400, unless a manual... They had to delete TH400 (M40) '75-newer because it would not "fit" due to the catalytic converter.

Make sure the TH350 your brother has lined up is for Buick, Olds, Pontiac and Cadilac. A strictly "Chevy" bolt pttern won't fit the Old OR Pontiac engine.

Jim