As we indicated, the Kenne Bell 2.8L blower is capable of supporting over 1,000 hp on the proper combination. After all, we saw the smaller 2.4L produce 960 hp on a smaller 4.6L. There's plenty more power to be had from this combination, especially once Kenne Bell cures the restriction in the throttle body and MAF. Producing 700 rwhp is a simple matter of an inlet upgrade, while there's a ton of power left with more boost.
Naturally, we'll check back with Kenne Bell on this GT500, and we'll also look into other mods once they become available.
 Equipped with the stock Eaton...  Equipped with the stock Eaton supercharger running a 3-inch blower pulley, the 5.4L pumped out 481 hp and 462 lb-ft of torque at 8.7 psi. |  After installing the Kenne...  After installing the Kenne Bell blower upgrade (with the same 3-inch blower pulley), the peak power numbers jumped to 610 hp and 567 lb-ft of torque. The installation of a 2.75-inch pulley upped those figures even further to 656 hp and 641 lb-ft of torque. |  |
GT500-Stock Eaton vs. Kenne Bell Blower Upgrade
Well, fellow Mustangers, it looks like the guys at Kenne Bell have done it again. Check out what happened to the 5.4L Four-Valve GT500 motor after we replaced the stock Eaton supercharger (running a 3-inch drive pulley) with the new Kenne Bell twin-screw blower upgrade. The kit featured the massive 2.8L blower capable of supporting 1,000 hp or more. Run with the same 3-inch blower pulley, the larger and more efficient twin-screw provided roughly 4 more psi of boost, from 8.7 psi to 12.7. The Kenne Bell blower upgrade improved the power output of the 5.4L motor from 481 hp to 606. Naturally, the increase in boost offered serious torque gains throughout the rev range.
Kenne Bell Supercharged GT500-3-inch vs. 2.75-inch blower pulley
As if over 600 rwhp wasn't enough, we decided to take things to the next level. By replacing the 3.0-inch blower pulley with a smaller 2.75-inch version, we increased the boost pressure to 14.5 psi and the power output right along with it. Running the same timing and air/fuel ratio, the additional airflow (and boost pressure) supplied by the pulley change increased the peak power output from 610 hp to 656. As always with a positive displacement supercharger, the power gains were every bit as impressive through the entire rev range. The peak torque jumped from 567 lb-ft to an amazing 641.