Quote Originally Posted by nitrowarrior
Just a note to go along with Hopper's idea. THe THM400 has heavy internals to spin. Closer gear splits and not evenly set on the planetaries. It requires more torque to drive the unit under load. Take the gears down to a more suitable set (3.50?) and strongly consider a different tranny. Q-jet is set up for???? They can be tuned to bring this set up around big time.
With all the torque the 400 sbc makes I don't know if you would ever feel the differance but you might notice it at the track.
Keep in mind this 400 sbc is swinging a 3.75 stroke the same as the 396/402.