Wrong.
The 302 heads are closed chamber and will help raise compression.
They will flow fine on the 318,they will help with low end and throttle responce.
Yeah and if this were a big block that would be like taking off your 906s to put on some 516's. The 302 head flows less than a regular open 318 head without a considerable amount of work.
If compression were everything we would all be driving diesels.
The 302 doesnt flow the peak till a lot higher lift...because it's like a gopher trying to stick its head out of a hole.
I'm not into plugging my youtube...but I flow it in a video and then do a better valve job and relieve the chamber around the short turn. It's a big difference.
Whatever you read about you better read again. That head as cast is a piece of ******* ****. I hate sounding like this but dude I've been here and done this, I have many names... if you read ...I dont lie.