Ford Modular Motor Forced Induction Testing - Force-Fed Foursome

500hp 4.6L Kenne Bell Supercharger (9 psi)

This buildup began as a '98 Two-Valve motor with more than its fair share of miles. The high-mileage but otherwise stock short-block was topped off with a set of ported PI heads from Total Engine Airflow. The power potential was further improved with a set of XE274H (non-PI) cams from Comp Cams, a 75mm Accufab throttle body, and 1-5/8-inch Hooker headers. Installing the PI heads on the non-PI short-block increased the static compression by nearly a full point. The result of all these modifications was a normally aspirated Two-Valve motor that produced 407 hp and 393 lb-ft of torque. After replacing the factory PI intake with a Kenne Bell 1.7L twin-screw blower running 9 psi of boost, the peak power numbers jumped to 574 hp and 513 lb-ft of torque.

As we have come to expect, torque production was impressive with the positive-displacement twin-screw blower. The torque production exceeded 500 lb-ft from 3,700 rpm to 5,700 rpm, making for one sweet powerband. As with the FRPP combination, the Kenne Bell blower had significantly more power to offer with increased boost pressure. Though the Kenne Bell blower kit included an air-to-water intercooler, after testing we were a little concerned about the strength of the factory cast pistons. If you want to produce near 600 hp, it's best to step up to some forged internals-at least pistons and rods.