i tried searching but i couldn't find it, are all flexplates universal? i have a 700r4 but im thinking of buying one off of a guy but i think his transmission is a th400, is it just the teeth that matter? im pretty sure both are 153

 

The hole patterns for the converters may not match up, not sure on this. When I bought mine I made sure it specified that it was drilled for "universal" application or specifically mentioned the 700R4.

 

Don't forget also that crankshaft bolt patterns for 1 piece and 2 piece rear main seals are different so you'll need to find the appropriate one.