I just picked up a project 360 engine this past weekend. It's a 1974 block out of a van and it came with a pair of 915 casting heads. One is a J head but the other is a U head. My understanding is they are basically the same head, can I use these on the same engine or should I start looking for either a J or a U head to have a matching pair. The bores seem really nice so my plan was to maybe take it to the local machine shop for a good cleaning, and hopefully only a hone. I was planning on using the Edelbrock Performer that's on a 318 in my Dart right now and also use the Holley 4160 600 cfm carb that's on that manifold. A good fairly mild cam and I should have a cheap but fun engine. My main question is the heads, though. Will a J head and a U head work well on the same engine?