Do a 496, just bore the block +60 (4.310 bore) We have some killer deals going on kits right now. As for a Camshaft, I would do custom, This can be custom tailored to specific heads to target mid loft flow numbers for peak power. As for the trans, your gonna disintegrate it. Turbo 400 or Powerglide is highly recommended. Heads, RHS, Dart, AFR, World, these are good choices depending on your budget. Runner size I would stay around 320-325cc