71 and 67 318 heads??

The 302 heads are a direct bolt on, no changes. The intake ports are pretty narrow thru the pushrod bulge and that area should be shaved down as much as possible. If you get a set you'll see what I mean. You can find these heads on just about any late eighties thru early 90's 318's, diplomats, vans etc will have them. Make sure to look for heads that have 5 valve cover bolt holes and the last 3 digits of the casting are 302.