Earl Moorhead wasn't a believer at first. Accustomed to using a centrifugal blower on the strip, he was reluctant to try a twin-screw supercharger. Now, he's not only converted, but he's also setting new standards. What's his best time to beat? Try 9.94 seconds at 140.71 mph. Granted, that's not such an unusual figure for a built engine or one hitting the bottle, but Earl claims his '03 Cobra is the first to make 9-second passes with a stock 4.6-liter block--and that's with no nitrous, no automatic, and no B.S.
All the power comes from above, delivered by a 2.4-liter Blowzilla set at a whopping 26 pounds, good for more than 700 horses. To prevent detonation at such high boost levels, Earl condensed the air charge by adding a Vortech chiller with a billet water bottle custom crafted by Precision Fabrication. "It also works great on those back-to-back runs," he says.
The only internal changes on the engine were hotter Crower Stage 2 roller bumpsticks and stiffer valvesprings. "The cam setup Crower gave me solved a lot of problems with valve float," he says.
After several hard runs, Earl pulled apart the engine to inspect the main bearings. He then added ARP head studs to keep things tight--otherwise he maintains the innards are factory original.
On the intake side is a custom cold-air kit from Earl's Automotive (Moorhead's shop) which uses a K&N filter. Accufab provided the throttle body, and the mass air unit is from Superchips Custom Tuning.
The pulley system for the blower uses a 9-inch wheel on the bottom and a 31/4-incher on the upper. With that setup, the dual lobes of the blower case spin at 16,600 rpm, whirling out a 1,200-cfm tornado.
Keeping pace with those gale-force winds requires spraying a fire-hose worth of fuel. Earl upgraded the stock injectors from 39- to 60-pound units and installed dual lines on the primary fuel pump. One nagging problem, though, was that the fuel system would go into safe mode when the boost levels began to climb. Earl finally figured out how to modify the pump's driver by soldering off a chip on the circuit board. "That one took six months to figure out," he says.