hi i have a th400 tranny and want to put a shift kit in but the car has ben toyed with a little and i dont want to buy one if it already has one. so my question is how can i tell if i alredy have one and if i dont which is the best one for around 350 hp.
(i know the th400 is overkill for this hp # but it came with the car.)

 

shift firmness...

if it shifts harder than any stock automatic you've ever driven... it has a shift kit... they are pretty noticeable

 

shift kits are very noticable. All shifts are short and hard. First to Second should give u a pretty good jolt, and mine chirps the tires at anything over 3000ish RPM on the 1/2 shift.

 

The B&M valve body kit usually produces harsh part throttle shifts, while the Trans-Go (when installed correctly) will give fairly smooth part throttle shifts.