Bruce:
pretty cool setup you have there, i like it!
as for air motors
many years ago, while we were slow in the shop,, i decided to do a bit of testing on a smog pump
if you stuff air into the outlet port they make one hell of an air motor
they consume lots of air, but what air motor doesn't?
peak at about 3000rpm, and make tons of torque down at lower rpm
if i recall we measured the torque and got about 3 hp out of one at 150psi
i made an air power winch out of a pair of them, one for up and one for down
it would lift a 750lb transmission much faster than you would want it to.
scrap yards used to be full of them, and they were pretty cheap from there
if someone wants to play with an air start motor, its an option
bob g