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2009 Cobra Jet Mustang - History's Cobra Jet

We show how the FR500CJ Mustang stacks up against its predecessors

Photography by CC archives, , Ron Lewis/Ford Racing

Drivetrain
Here's where the real work started. Calvert's crewmembers Matt Bernasconi and Mike Hernandez are the two main thrashers, and they also work at Calvert Racing. Two cars were delivered on December 27 as delayed Christmas presents with a dangerously short lead time to be competitive race cars by the second week of February's Winternationals. The decision was to have four cars altogether with each car in a different class spanning A/Stock, AA/Stock, A/Stock Automatic, and AA/Stock Auto. The only real difference between A and AA/Stock is the AA cars can carry 0.5 lb/hp less weight (at 425 hp, this means the AA cars are a touch more than 210 pounds lighter) and therefore have a quicker index. Stock Eliminator is a unique eliminator because you must qualify, but as long as the car runs under its class index, it runs against a dial-in. If the car runs more than 1.4 seconds under the index any time during the race, the index is subsequently adjusted downward. This is something you try not to do, since it makes qualifying more difficult.

Mike says the six-speed in the Rice-Holman car that Calvert would drive was balky to shift right out of the gate, so the unanimous decision was to pull the G-Force four-speed trans out of Calvert's '68 CJ Mustang and stuff it in the new car. "That," Matt admits, "was a lot tougher than it sounds." It also demanded a much better clutch, so the call went out to McLeod for a bellhousing and a clutch. McLeod is now under new ownership, with original entrepreneur Red Roberts back in the hunt, providing the Calvert crew with a McLeod Modular bellhousing to adapt the G-Force to the modular 5.4L motor. McLeod also supplied a twin-disc Magnum Force clutch assembly that combines light weight and a diaphragm pressure plate to direct all that power back to the factory-installed 9-inch using a Ford Racing aluminum driveshaft in between. With the Cobra Jet's obvious sub-10-second-e.t. potential, a production 8.8 rear axle assembly would have been of questionable durability, so Ford stepped up with a completely fabricated 9-inch housing. Calvert chose to run 35-spline Strange axles and a spool with this combination spinning a 4.57:1 Pro Gear assembly. Strange also supplied the rear brakes.

While the cars originally came with a set of Goodyear slicks mounted on Cobra Jet-spec Bogart aluminum wheels, Calvert's car pulled up to the starting line with a pair of 30x9.0-15-inch D07 compound Hoosiers using Bogart 15x10-inch wheels. The 28x4.5-15-inch Mickey Thompson front tires are mounted on M/T aluminum wheels.

The unique shifter arrangement was more about not cutting up the car than anything else. The shifter in the stock location is the Reverse handle. To shift, grab the main shifter and curved handles, squeeze them together, and push the whole package forward into First. Still squeezing the two handles, pull straight back for Second gear. This is a Long-style vertical gate shifter, so to hit Third, release the curved handle and push forward, then pull back for Fourth. Do all that exactly at 6,800 rpm, don't lift, and make sure to use that clutch pedal because a clutchless trans is illegal in Stock Eliminator.

This is the two-disc McLeod Magnum Force clutch and flywheel assembly. Note that it's a diaphragm unit with an aluminum flywheel and sintered iron clutches. McLeod also makes a Soft-Lok clutch that is based on a fully adjustable, three-finger, Long-style pressure plate. A predetermined amount of slippage on the starting line makes these racing clutches repeatable and reliable.

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