So this summer I plan to lose my stock motor viginity and build a motor on a stand! But I'm in need of some help and direction.

I'm debating back and forth between a 3800 or a SBC.

Either way, I have a few questions:
1. If I don't want to "rebuild" per say, like the rotating assembly is is good shape, do I need to do any machining? Minor machining is fine but I wanna avoid costs in that department.
2. If I replace all the bearings, is it okay to reinstall stock rods and crank without machining?
3. If I do get a block that's .030 over already, pistons need to match right? What about the rest of the rotating assembly?

Thanks in advance, also gimme some votes on 3800 vs SBC! Lol