Its a pretty difficult conversion I once contemplated. The engine has a
heavy flywheel since the trans has no torque converter at the engine.
Perhaps a Buick crank setup can be used, since it used that 2 speed
with a torque converter. I think I still have that flex plate, its available.
Then there is still the matter of an adapter plate to mate them. The
TH400 came with a lot of different bell housings, but I prefer a BOP
switch pitch version. Bruce Roe