Well I have MMR's Stg 3 Heads. Rebuilt with all new and upgraded Valves, Guides, Retainers. I have a stg 3 Comp Cam N/A grind. (242*/246* with .552/.552 lift. on a 113) I spin mine to 7300 rpm, and still was mak'n power N/A. But hey... call and ask a few builders... MMR, VT...etc!