Had them on my 383 in my race car. Are you sure your pistons are a tenth down hole?(that's a lot) I was running flat tops that came .020 out, witch is factory.
67 383 was not .020 out of the hole but a 69 383 Road Runner was out of the hole.
Next.
Why would you want to put big valves in a small Port head.
The 452 are great heads use them.
