318/ 302 heads differences

well....ALL 318's come from the factory with 1.78" intake valves, and 1.50" exhaust valves.

360's on the other hand, come with 1.88" intake valves, and 1.60" exhaust valves.

360 cylinder heads also have more "port volume"....in the intake port.

302' casting 318 heads are closed chamber, and have heart shaped chambers.....and are known as Swirl Port heads.
308' casting 360 heads are not closed chamber, and do not have heart shaped chambers....they are "supposedly" swirl port like the 302's but dont get me to Lying.

might sound like negligable difference.....but you asked.