I am confused about selecting the proper compression ratio for my 498 build. I hear a lot of people say do not run over 9.1 with cast iron heads or 10.1 with aluminum on pump fuel. Are they talking static or effective compression ratios? After playing around with the calculator on the KB web site it seams to me depending on cam selection that you can run a much higher than 9.1 static compression engine on pump fuel, or is my thinking way out of the park. If so are these calculators accurate for real world applications. Any comments on this subject would be of great help.