Even so, 30HP more than stock would probably be a good guess as to added power from the head.......but no one would "just" port and polish and instal large valves without "other" work as you have done. I imagine a decent estimate where you are with power is probably somewhere close to 1 HP per cube. Maybe. Find a chassis dyno somewhere and make some pulls. But get ready to be disappointed. I believe if you come up with 150-175 HP at the rear wheel, you'd be doing good.
