J heads $200, snag them with the quickness? FEEDBACK PLZ!

If you pop those heads on a 318, your compression will drop - the 360 heads have a larger combustion chamber than the 318 heads. As long as they're off the motor, and you're gonna polish up the ports, you might as well mill them a bit too. And you should use a 360 intake, the port sizes are different (larger) than 318 heads.