I like to keep trucks as trucks myself but if you are going to do one your way..........
1) I'd go with a new MII type kit that is made for your frame or the S-10 kit from AD-Engineering, which has high praise from users both on this board and others. I'd steer clear of cobbing in a used suspension. By the time you rebuild it you probably have as much in it as the new one and it won't look near as nice.
2)Heck yes use the Pontiac. Everyone and their mother use Chevy 350s and it is very boring at car shows.
3) I put a 2000-4R behind a 6 in my '54 GMC. I found a floor center from a hydramatic truck and cut the original floor as needed to clear the tranny. I also had to notch the rear crossmember where the original bellhousing mounted. Go to my
54 GMC page and click on "Transmission".
