I was offered a 472 big block with a th400 tranny to put in it.
Cadillac I presume.
Just out of curiosity has anyone done this or would it even work?
Its been done. I've seen pictures of others having done it, and I've put a Cadillac 500 in my '55 1st GMC. It is a tight fit.
If so what all would I need to do? mounting brackets etc.
You are going to be fabricating your own front mounts and modifying an aftermarket rear crossmember. You will need to move the steering column. Custom exhaust and perhaps shave the frame on the passenger side to fit the exhaust manifold.
and could I use the new wiring harness I just installed its a 12V system already.....
Sure.
The question to ask yourself is WHY are you doing this. Its going to be a lot of work, with lots of little changes, and if you don't have a clear goal in mind it might be hard to finish it.
