I'm running 9:1 360 with 508 Mopar cam, same gears and slicks as you are. My Demon was using a 9.5" 3500 stall, switched to 8" 4600, car went 6 tenths and 5 MPH quicker in the 1/8. I race 1/4 mile tracks. Right now I go through the lights at 6200 at 114 MPH. Swap the converter, leave the gears alone.