308/318 Heads
** I'm building a 318/390 stroker.
So rule out the 302's. Even the stock J's or 308's are going to be your limiting factor for making power on a 390, you're going to have a hard time getting over 400 hp with any stock head even with the big valves.
I've got a set of ported 308's that flowed 264cfm @ .500", so you can get great flow out of them, but after porting, opening up the valves, milling etc the cost was pretty much the same as buying a brand new set of Indy/RHS X-heads with all the goodies, and those will flow just as much, if not a bit more, than my ported heads straight out of the box, AND get you a closed chamber head AND still have more room for porting.
I think that for any of the stroker engines now, even a 390, your best bet is a set of aftermarket heads. The cost has come down to the point that by the time you've fully rebuilt, ported, and bought all the necessary goodies for a OE head you could have bought an aftermarket head with all the goodies already on it that will match or outflow the ported OE head.
