302s aren't that hard to find?? At least I didn't have any trouble finding any. I guess it depends on where you live or where you look.
PS - Just for fun I threw in a pic of one of my "machined" magnum manifolds next to a stock 318 manifold. The difference is DAY and NIGHT!!! That's why the exhaust sealing surface has to be so large on the 340 driver and the 360 passenger.....more FLOW!!!!
Treblig