Tom Wilson
December 1, 2005

Horse Sense:
We received a phone call from Carroll Shelby once. When the secretary said there was, "a Carroll Shelby" on line five we didn't believe it. Would you? Turned out he was calling to chew us out for calling it an, "AC Cobra."

You have to admire Carroll Shelby for still playing the game. After all, the man flew during World War II, had a great career as a driver (he won Le Mans way back in 1959 in an Aston Martin), built the most revered sports cars in the U.S. and possibly world-wide history (the GT-350 Shelby, 289, and 427 Cobras), won the sports car constructor's championship in 1965 (the one and only time by an American), helped make the original GT40 a winner, brews great chili, runs a successful philanthropy for children, and is back with his name front and center on the new Shelby Cobra GT500 from Ford.

That might be enough for a lifetime, but Carroll can still be found running from one event to another, building cars, working his children's fund, and generally staying in the spotlight. And to that end, here we are, tagging along on a dyno test of one of Carroll's personal engines. At press time, it wasn't known if it was going in a '66 GT350 convertible or a Cobra (the two-seater with no roof, not the Mustang namesake more common in these pages), but it was going to be one or the other.

No matter, really, as with 525-plus lb-ft of torque and always more than 500 hp, it will do the job nicely in either chassis.

Built at Trans Am Racing by Mark Jeffery, the engine is a 427ci stroker Windsor. Befitting the early cars it is destined for, the engine is carbureted, and as such, could go in any sort of modern toy-car Mustang. As you'll see, the combination of generous displacement and conservative compression and camming makes this an easy-to-drive, yet satisfyingly powerful, powerplant. Lightly constrained with big dyno mufflers, the 427 was between 505 and 526 hp depending on the induction, and growled out 518 lb-ft of torque at its worst and 531 lb-ft at its best. Considering the small camshaft, these are good, car-moving numbers that ought to replicate easily in the real world of 211/42-inch exhaust, tight-fitting hoods, and the like. And unmuffled, we saw 529 hp and 541 lb-ft, which ought to be fun on track day.

Our testing included an exceptionally well ported Edelbrock Torker II single-plane intake, a not so heavily modified Edelbrock RPM dual-plane intake, and a pair of carburetors-a Pro Form and a 650 Mighty Demon. While the trick, ported intakes are a bit of a curve ball, the single- versus dual-plane data is always good to review (modern dual-planes are tough to beat), and we had enough time to fiddle with the mufflers, too.