I think that you are telling us a lot when you say you want the externals to be the stock components. Carb, heads, exhaust manifolds etc. So tell us what your goals really are for this sleeper motor? You can spend huge money having the stock head castings worked, but if you are going to use the Rochester carb and stock exhaust you will be wasting the money IMO. If you cannot get the fuel/air in and you cannot get it out where are you headed?