IO would rebuild it stock, all new parts except castings. KB makes a flat top piston, that with a steel head gasket and a touch of milling will get you decent pump gas compression with iron heads. The hedas will need unleaded seats, so it may be wiser/easier to locate a set of 452 castings (visually almost identical) and do them up for it. Properly degreed, the stock cam and 9.5:1 will chirp tires all day. If you want more pep, add a slightly larger cam, with matched springs. You wont be unhappy if the work is good.