First question, what's your budget for the "complete" motor?
Carb to pan, headers, distributor, plugs, wires, oil,..... Everything.

Then, is your car currently equipped with a fuel and cooling system capable of supporting a 650hp motor?

If not, are those upgrades budgeted separately...... Or do they need to be included in the "engine" budget?

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads