340 valves in 318 heads???

After all the head work. Seats, Guides, Valves, Springs, and Probably shims Blending the bowls . Add up what you'll have into them in $$. You'll still have small port 318 2bbl heads. For a little more cash you can buy a new set of 360 or aftermarket Alluminum heads. Then you'll see a power increase . Just more bang for the buck. Eddy heads are a real reasonable buy right now.