5.7 eng., 400 turbo? unmounted the tranny today. This things been worked on before supposedly by gm. it's ran like it had a parachute behind me since I've had it. when I was pulling the tranny I noticed it had a 6 pad converter with only 3 bolts in the flywheel. the other 3 holes didn't line up with the holes on the TC. thats to say there are 6 holes in the flywheel but they're not in a circle, like 3 holes of one circle are smaller than the other 3 hole circle ( hope that makes sense). trying to figure out what TC matches the tranny. GM is not much help even with the serial number. Of course they want you to go to the dealer. need to know how to determan what the right TC is.