In case you missed it the stock heads made damn near 400 hp, I’m not impressed with the AFRs on this 340. Maybe if it was 400” with a cam in the 250@050 duration range the difference would be more…
I would have liked to see how the heads they didn’t run would have compared, the heads he put together for the engine and took off to run the stock heads.
Could you port out stock heads to make these and even higher hp numbers of course you can, but the point is most are not and glad they can just order a set of 450 hp +heads, if that's not for you and some others here that's fine and port away.
I'm not making a case to buy AFR heads, to me all this test shows is decent power can be made with reasonable parts if you rather do it with ported stockers go for if some rather TF's or SM or W2 or whatever heads then do.