I'm a major advocate of...."to each his own" BUT....I think you would be making a BIG as in HUGE mistake pulling the 472 and sticking a chevy in there. No need to tell you that the car is very heavy and you need cubes to get her rolling. Besides, you say you've never tackled anything like this before so you might just be getting in over your head with all the computer and electronic hook ups and such for the engine and trans. Don't know your level of expertice....maybe you can.
If you go to Cadillac Forum
you can join the forum of guys that build some "rip snortin" 472/500 Cadillac engines. There's plenty of hipo parts being made for them. I've got right at $6700 in my 507" Cad, it dyno'd at 535 trq. @ 4300 and 466 hp @ 5000. And this is an 8.7:1 engine that can run on 87 oct....think about it. ps, the red line is the torque curve....which doesn't curve too much