I Need Help!
As far as the input shaft of the trans goes, I sold a '68 318 to a buddy to resurrect his '66 Barracuda S. He ended up using an adapter bearing to use a 4 speed with the crank drilled to the AT pilot.
As far as engine balance goes... if a convertor can have balance tabs on it, why couldn't an flywheel have an offset balance?
What about a flywheel from an '80's truck?
-bill