Rule of thumb says = normally aspirated you can get 2 h.p. per each cfm of intake flow on the flowbench, if the exhaust flow is 70% or better.
Using that...... you can't reasonably get 500 hp with those heads.....
of course, horsepower IS based on RPM.
Last edited by xntrik; 04-13-2006 at 02:27 AM.