I was wondering if anyone has a calcualtion on what percent of horsepower you gain for how many 10's you shave off a head? And if so what would be the limit of milling on running on street gas if my compression ratio is 9.5:1?

 

I see your point but there really isn't to much they can shave off in the first place. Even if you take them all the way down you are talking about maybe 10hp. Now if you wan't more power then get more air and fuel down in there in the first place. Port and Polish heads, Cam or lifters, TB, CIA, Full flow exhaust. You can always go after market heads too with the others.