1978 318

Never heard of a 318 that used 360 heads unless it was a police car. I replaced the head gaskets on a buddies 78 Fury that had a 318 and they were the standard small valve heads I saw on all late 70's 318's. Putting 360 heads on a 318 will result in a dramatic compression ratio drop putting it well down in the 7's. That's because the combustion chambers of the 360 heads are several cc's larger than the 318's. I wouldn't expect more than 200 hp from one unless a bunch of other stuff is done.