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With the 408 strapped to the Superflow 902 dyno at Westech, we spent the morning dialing in the engine's air/fuel ratios and experimenting with different sized pulleys. The best street combo was a 2.75-inch pulley and 91-octane gas. Once dialed in, we nailed a best pull of 778 horsepower at 6,600 rpm and 710 pounds of twist way down at 3,700 rpm (11 psi of boost). For giggles we bolted on the 2.5-inch pulley and dumped in 114-octane Rocket Brand race gas. Our reward was 803 horsepower at 5,650 rpm and 813 ft-lbs at 3,700 rpm. We had to stop the pull at 5,650 because the injectors were maxed out! After checking the dyno we were hitting over 20-lbs of boost, so we put the 2.75-inch pulley back on and called it a day. After all, this is for a street car.