318 Compression ratio

Screw RHS heads, all that money and they're still iron and won't let you bump compression past a pump 93 safe 10:1. . . no thanks.

302 heads can easily attain your goal, we are working on a set for my lil bro's SBE 68 318, port matched to 360 gasket size, good single plane intake, mid 500 lift solid cam, and it should suprise some people for very little money, the trick is he is starting with a 68 318 with a forged crank, and will be doing nothing more that a re-ring and bearing job along with milling the heads a little. We will probably upgrade to larger valves and try to use some with a skinnier single groove 11/32 stem as I did on my X heads, Also Comp has a beehive spring that can be used with the single groove valves and 10* locks, they work great with my .520/.540 solid cam.

When it comes to porting go for it, as mentioned it is satisfying. Don't be scared to read up on it then practice on maybe a spare set, do a few ports then if you feel comfortable lay into the 302 heads.