So here's what I got when I took these heads out of the box: ( no pipe on exhausts ) 0.100" = 55 / 46, 0.200" = 113 / 95, 0.300" = 175 / 129, 0.400" = 207 / 153, 0.500" = 228 / 166, 0.600" = 223 / 172 I wanted to have my cake and eat it too: Improve low-lift intake flow, solve the problem of the intake ports flowing less at 0.600" than at 0.500", and serious exhaust flow. But look at the intake flow at 0.300", you'll see it it's difficult to have it both ways. Again, no pipe on exhausts 0.100" = 61 / 53, 0.200" = 124 / 110, 0.300" = 181 / 144, 0.400" = 223 / 171, 0.500" = 243 / 186, 0.600" = 242 / 195. I still have this exact pair of heads, I was thinking turbocharged 327, and now that I have a 4.10:1-geared Dana 60 under my '84 Trans Am, and a set of 3.54:1 gears for it, I'm thinking this may be the solution for my boredom. Alternately, I could sell these for enough to do either a mild-turbo 350 Vortec, with a 206/224-111 cam, or maybe try a carb'd LO3 with a Magnum 270 HR Anyone have any questions, comments, suggestions or opinions?