To run 9.50’s@3300lbs at a track with a little elevation.......you’re going to need the motor coming off the dyno at about 775-800hp........ to have 725hp uncorrected as the car sits on the starting line.
I aint got a finger in this fire , and my 505 doesn't run as good as it should , but I have read , and been told that a well ported set of the indy heads will flow over 400 cfm , putting them up there with rat heads.
An ex aquiantence and my ex partner ran a duster that would run low 9`s w/ those heads easy, he had to back the carb down to about 9.60`s to keep from splitting the block.
