Your stock heads will be fine. If they need rebuilding then do a price check on rebuilding and already rebuilt heads. The problem is *I Think* your living in the past on prices. The hobby is not cheap and a grand for rebuilt heads is possible in some markets but not mine and so that leaves the upgraded heads like Edelbrock which are replacement performance heads at the increase cost which would probably be cheaper than the like OE head rebuilt and ported to match the aluminum head.