As the results show, the big KB is no joke whatsoever on the Boss 302. Once tuned (we used VP Racing Fuels' C-16 blend), the blower easily makes killer power across the entire 2,500 to 7,000-rpm rangeùwith either pulley installed. Interestingly, peak torque from the twin-screw-blown Boss is reached at approximately 6,000-6,200 rpm, roughly 1,000 revs past the peak for Coyote 5.0s equipped with the same supercharger. We attribute this difference to the Boss engine's superior breathing and Jon's ability to manipulate the valve events specifically for exhaust.
Yes, we did fall just shy of making 800 hp at the rear wheels. However, if you're thinking 785 hp is "it" for this combination, you're horribly mistaken. What we learned in this exercise is that the '11-'12 5.0 Mustang's mechanical-returnless fuel system understandably has a limit. A lack of fuel at the higher side of the rpm range ultimately led us to stop just shy of eight-hundie, as there was no way to compensate for dangerously lean air/fuel ratios.
Bolting a Kenne Bell blower on a stock Boss 302 instantly gives the specialty 'Stang even more street cred than the Pony has in its original trim. On the street, stock rubber doesn't have a prayer in First, Second or Third gears. However, once the tires actually do grab, acceleration is furious and the speedo is well beyond 100 mph in seconds.