Cab, I did all the reseach I could about these under performing heads and what I noticed was they need 12:1 minimum compression to perform well. Anyone running these heads with less than that were not getting good results IMO. I don't know what Edelbrock did with these ports, but i'm thinking there shaped wrong. I know Dwayne said the valve is almost the same size as the port throat under it. I think the Indy tunnel ram with the Thumper 750's will easily put me into the 9's. Then a cam change to something more aggressive and maybe 9.80's or better? I could have run it with the air clearer or the 4 hole tapered spacer and busted into the 9's, but I ran out of fuel. I can't believe 7 or 8 gallons of fuel was used in 6 passes. Where did all that fuel go? Thought I had plenty, but it cut my day short.