You can find 4-bolt mains 350 blocks around everywhere. They are falling out of trees. If you were to get something like that, I doubt that you would have to do much extensive work to it past bolt-ons to get the type of performance you're probably looking for in a car of that weight. I am not the most experienced person here by one heck of a long shot, but I'd say the right head, cam, and intake/carburetor package would give you plenty of wallop to propel a car of those dimensions.

A popular choice seems to be the Edelbrock Performer RPM Aluminum cylinder head. I've heard great things about them, and was going for a pair myself when I found myself a pair of brandy-new Dart Iron Eagles for the right price.

I know that a few people did LS1 swaps into those cars with insane results.

It's cool that you're getting into V8s. I'm only 20, been into them for a few years now, and I love my old-ass technology to death
As far as the engine tech aspect of this project, you've come to the right place. I've yet to have a question left unanswered. Half these people have built more engines than I've had hot meals.

Good luck to you.
-Rob