Selected dyno runs from Kenne Bell’s voluminous testing regime are shown here. Careful attention to reducing variables makes this data accurate, but just the same, don’t bother picking one or two horsepower nits here. The trend to better power from the 5.0 at higher rpm is clear, and that’s the important point. Of course, the blown 5.4 looks pretty good in the midrange. Keep in mind that the first GT500 test was with the stock Eaton supercharger, while all the rest were with Kenne Bell’s 2.8H blower.
There is no 18 psi of boost run for the 5.0 because the two times the test car was tuned up that far, it blew up its oil pump. Yes, the oil pump. This happened because to get past 15 pounds of boost, a larger crankshaft pulley is needed, which means changing the integral harmonic dampener. Something in the aftermarket dampener and the oil pump didn’t get along, resulting in a shattered inner oil pump gear each time the larger aftermarket damper was tried. A stronger pump gear will soon be available to cure that problem.