318 build #2 "cost minded" for the '74 Duster
Add 1.88 valves (or bigger if possible, IDK4 sure) leave the exhaust valve alone, give it a full porting, let’er rip potato chip!
But they only go so far. They would be a great 318 head and OK & fine for a 360, but I don’t remember seeing hearing that they go much above 240/250 cfm.
IIRC, I think
@MOPAROFFICIAL ported some of these or other like 318 heads. He could tell you what he has gotten out of them. Also how they would compare to work done on a Magnum head. Equal work/flow or what it takes for each to have equal flow and who took more work to get there.