The buick is an overhead motor. I'm told that the buick bellhousing would mate up to the SM420. That's all I know though. I asked about this same swap over on Team Buick. I think it would be great, but my engine source evaporated, and that's as far as I got.
If you are switching to an open driveline, there is an adaptor available, to go from the 320 bellhousing to a T-5, but the adaptor is about $1000.
You'd need to make new mounts, blah blah blah.
You can find all this stuff, like SimS said, with your pal google.
