the carb is not too small for the engine. i consulted many hours with summit, barry grant and others on 650 over 750, even found an article in one of the magazines about a 500hp 302 at a dyno where they switched between a 650 mighty demon and a 750...there was no difference other than a drop in low end torque with the addition of the 750. The lift is short on the cam because of piston to valve clearence issues. But yes, i was expecting around 400 at the flywheel at somewhere around 6500 to 7000 rpm. Are the 1.5 inch diameter tri y's the best explaination for peak horsepower at under 5500 rpm?