Ford Mustang - 6.1-Liter Mustang Cobra Jet R - American Car

Six tasty alternatives to help satisfy your never-Ending appetite for acceleration

Everyone knows that there are plenty of ways to arrive ultimately at the same end point. For any true performance enthusiast, the real test involves getting there first.

In this special section, we've brought together some of our favorite high-velocity haulers, all of which are powered by engines designed to start your adrenaline flowing with a turn of the ignition key. Superchargers, turbochargers, multicams, multivalves, and last, but certainly not least, a plethora of plain old cubic inches-all are critical ingredients in the many possible recipes for speed. Topping off this cornucopia of motivational componentry, we offer a brief tech overview that details the specific manners by which these marvelous mechanicals work their go-fast magic. So, buckle up, hang on, and savor the tasty flavors of fast.

The Cobra Jet R is a secret, high-caliber weapon cocked and ready for firing.

Like an intercontinental ballistic missile, the Mustang 6.1 "CJR" is unholy firepower that cooler-heads at Ford Motor Company are hoping will never be unleashed from the Blue Oval bunker.

Hidden and developed covertly within Ford's high-performance SVE (Special Vehicle Engineering) fortress, this one-and-only 6.1-liter Mustang Cobra's existence until now was virtually unknown outside a small cadre of elite Mustang racing engineers. And so it would have remained had Motor Trend not caught the high-octane scent of this engineering prototype and pushed to give you a peek at what could be Ford's most muscular Mustang since the original Cobra Jet-equipped Mach I that debuted in '69.

After long discussions with Ford SVT (Special Vehicle Team) officials, the door was cracked open briefly for a full Motor Trend street and track test of Ford's secret Camaro-eater.

Inspired by Carroll Shelby's '65 GT350 competition R-models, the limited-production (250 units) 5.8-liter/280-horsepower Cobra R (MT, April '95) was created to do battle in the IMSA Street Stock Endurance Championship in the Grand Sport class. That required that the R's be built for showroom sale by special Ford SVT dealers and that they be street-legal. Frankly, the butt-bruising ride, lack of air conditioning, missing rear seat, radio deletion, and absent sound-deadening materials make driving one of these hot and hairy monsters as close as most drivers will ever get to sneaking a factory-built racer onto public roadways. Interestingly, however, though Cobra R's were built for the track, Ford reports rumors that the vast majority of the 250 have never been driven in competition. Instead, collectors have scooped them up as investments.

Although their competitive edge seems to have dulled recently, the Pontiac Firebirds in street stock were at one point looking too strong to crack with only the Mustang's 5.8-liter/280-horsepower OHV V-8. The Ford SVE group decided a bigger gun under the R's already bulging fiberglass hood might become necessary, so it began tweaking the basic 5.8-liter overhead-valve block.

The 70-horse deep-breathing exercise was pure and simple. No waiting for turbo boost or whining belt-drive problems. The bore was left at 4.0 inches, but the stroke was stretched to 3.71 from 3.50 inches. The light aluminum cylinder heads were ported, and bigger (1.94- versus 1.84-inch) intake valves were installed. Engineers then chose 1.6:1-ratio roller rocker arms and a wilder grind on the Crane roller camshaft. The bottom half of an SVO (Special Vehicle Operations) aluminum lower intake manifold was bolted to the heads, but for the upper half of the intake, a hand-crafted black aluminum plenum chamber was fabricated. Snorting into that aluminum box is a trick twin-50-millimeter throttle body coupled with higher-flow-rate injectors. The engine exhales into standard '95 Cobra 5.8-liter tubular exhaust manifolds.