Yes, and i think most do. The -1 head has always been a great head. The E Victor, not so much. Jesse told me best thing for this head was angle milling. Brad said he gained nothing going from 1.5 to 1.6 and he uses the same heads as me. Would had same result going from 1.6 to 1.5. I have no choice now but to put a 1.5 intake rocker on it as there is not enough v/p clearance for a 1.6, so if im comfortable with .050 on intake and .080 on exhaust i run it, if not a new cam is my next step. The cam can only be degree'd at 106, either way from that there is not enough clearance its that close.