Pick up a book called "Rebuilding the Small Block Chevy" and read into it some. I won't be building anything soon, but extra knowledge never hurt anyone
Here are a few different build-ups of different 400-based engines. Take tips and tricks from all of them, soak up the info like a sponge
http://chevyhiperformance.com/techarticles/6113/
http://carcraft.com/howto/1004/
http://www.chevyhiperformance.com/te.../148_0306_406/
also.. if you're gonna do a 400, just go ahead and make it one of the magical numbers like 427 or 454
