I used to have a 2 spet on my Trans Am, it is a built motor with heads, cam, and a 150-200 shot on top. When I had the 6spd it was almost impossible to be consistent at the track untill I put it in. I used a ligenfelter kit- overpriced but worked.

Since then I have put in a race prepped th-400 and big stall.

To the OP- I would never put a 2-step in a DD as it is hard o nthe tranny- and we all know our trannys are not the strong point in our vehicles.