What would be the best spark plug to use in my 451? Engine specs are: 14 cc dome pistons, 915 heads at 80 cc, 509 cam, 292 duration int and ex. 3.91 gears auto trans. 2400 RPM stall torque converter. C/R right at 13.3 to 1. Altitude, 5400 feet, Mostly strip use, some street. Holley Street Dominator