I'm building a 383ci stroker motor and I'm thinking about upgrading to aftermarket heads. Give me your opinions.....Airflow Research, World Products SR Torquer, Pro-Topline, Edelbrock, what is best? Aluminum or Cast Iron? Does anybody know where I can find some flow numbers for these heads? I found the flow numbers for the AFR heads and the SR Torquer heads. From those 2 flow numbers, the AFR heads are incredible.....according to my dyno software 433ft-lb Torque and 393HP! The SR Torquer only give me 415ft-lb, 321HP! I'm looking to stay in the 170-180cc intake runner range and 72-76cc combustion chamber range so that my compression stays around 9.25:1 compression. I don't think I want to go higher than that if I want to use pump gas. Oh, and my Cam will be a Crane Energizer 10005 (216 deg. duration; 112 lobe separation; .454 lift).