T56 Anybody?

Yes, it has been done. check www.montecarloss.com........a few guys have them in their cars. As far as behind a Buick V6. No one has done it yet since there is a lot of fabrication that has to be done with the engine to trans adapter/bellhousing and flywheel issues.
T-56's are not very tough, but if you just gotta have one, the ones used in the Viper have the best set of internals.

HTH :)