I mostly use the 270H head but Mike Kirby always sleaves the bolt hole close to the ports then does the port work. He only did one head for me and it is that way, my others are not. I have know idea what your plan is for the head but remember the 302 has a lot of shrouding on its valves so the bigger you go the more shrouding you have. I've use a lot of different size intakes and their effiency depends on what I wanted to accomplish. Torque, RPM, Blown, Unblown. Each has it's own needs. Unblown, it's the velocity when the valve opens that is your friend and makes for power, at least it has for me.
For me the 12 port head with no chamber was the best. (Wayne-Shinner) no shrouding at all.........Good Luck
