I dont believe you need to touch the valves to have the heads ported. But in return, by not adding larger valves you are still restricting the heads some. The valves are pretty small (I SHOULD know the sizes off the top of my head, but I am drawing a blank) and adding a set of GT-40 valves, with a good valve job, on top of the porting would wake those heads up like nothing! Some guys have run amazing times on E7 heads, you just have to soend the money where it counts!