71-85 or so are heads based on the J heads, with some minor changes and on trucks, after I think '75 had AIR injection holes under the exh ports. (not a problem, but visually different) 85-91 should have 308s, and you wont find them (360s) in anything BUT trucks after 80 or 81. 85-91 318s had 302 castings. It's the early to mid 80s where the "swirl port" stuff makes it into production, so what I've found is from 82-85 or so you may have regular or 308 heads...You never really know with Mopar...lol.