318 heads on a 360?

If this is a on the cheap project for power, you can get these heads to flow very well down low (Under .500 ) and port match the heads to a 340 window.
While there would be some limitations to RPM abilty, most larger (360 for example) engines with there stock larger port window stop making power by then anyway.

Your focus would be on making mega torque and useing it to your advantage rather than big HP numbers and high winding RPM's.