Back at the dawn of the musclecar era, a man named Carroll Shelby approached Chevrolet with a wild idea. He and a friend wanted to create a new kind of two-seat sports car using many Corvette components. In the end, GM brass finally decided not to participate. Chevrolet brass and engineers felt they would be competing against themselves if they became involved in the creation of another two-seat sports car.
GT350 Mustang and AC Cobra...
GT350 Mustang and AC Cobra production at the original Los Angeles production facility is seen here. It's hard to believe some of the most competitive cars ever built came from this primitive shop.
Shelby's plans lay dormant for a few years. He then approached Ford with the idea of placing a small-block V-8 engine into a beautifully designed, but underpowered, English roadster made by the AC Sports Cars Company. The AC Ace was smaller than anything produced domestically, and former bomber pilot and auto-racing veteran Shelby felt that here was a good platform for a new kind of high-performance car.
This is the 289 Fairlane V-8....
This is the 289 Fairlane V-8. The high-power potential and light weight of this engine made it an ideal choice for the little Cobra platform.
This time, the engine in question was the new 260ci V-8 introduced in the '62 Fairlane. Shelby got the engines he wanted and, using a facility in Los Angeles, mated the new Ford small-block with the AC car. Thus began production of one of the most notorious sports cars of all time.
This is an original small-block-powered...
This is an original small-block-powered "slab sided" Cobra. The lack of fender flares and the wire wheels give these beautiful 289 Cobras a low-key and classic appearance. Don't let the gentlemanly look fool you, as even in street trim these cars were fierce competitors.
Although the first small-block Cobra used the 260, the 289 was soon adopted. The Cobra was then offered at selected Ford dealers. By the time these cars began to appear on the streets and road courses of America, there wasn't much Chevrolet could do. Although the more powerful Sting Ray was a potent car, it was larger and much heavier than the little Cobra and, hence, in any kind of speed contest the smaller car usually trounced it. In 1965, Chevrolet introduced an advanced all-wheel disc-brake system for the Sting Ray and a new 396ci "big-block" engine. These improvements made the Corvette an even better car, but it still couldn't keep up with the Cobra, as a rule. When the extensively redesigned 427ci version of the Cobra was introduced, the performance gap between the Corvette and Cobra opened even wider. With only 100 or so of the original big-block Cobras produced, they are very difficult to find and extremely expensive.
When the Mustang was introduced, Shelby immediately recognized that the characteristics of this interesting car gave it the potential to also be a great road-course contender, and the GT350 was born.
Indeed, the light weight and great balance of the Mustang made it one of the all-time great road racers. Let's look at the very effective changes made to the '65 Mustang by Shelby to create the GT350. Keep in mind the changes made by Shelby for the GT350 will work just as well on your Mustang.
The FE 427-powered Cobras...
The FE 427-powered Cobras had a redesigned chassis as well as more power. With a 0-100-mph time of 8.8 seconds, these cars were nearly unbeatable in the hands of a skilled driver.
Under the hood, all '65 Shelby cars began with the K-code 289, which was relieved of its restrictive cast-iron exhaust manifolds. Tri-Y configuration headers were then installed. Although the cast-iron manifolds used on the K engine were the high-performance variety, they were still quite restrictive when compared to headers with individual primary tubes. These headers led to glasspack mufflers, and the tailpipes were terminated just in front of the rear wheels. This abbreviated tailpipe also helped reduce exhaust restriction. Exceptions to this were cars bound for California, Florida, or New Jersey, which received an exhaust system that led all the way out to the rear of the car.
The GT350 shown here is a...
The GT350 shown here is a '66 version. It has the clear rear quarter-windows not found on the '65 cars.
On top of the engine, the usual cast-iron intake manifold was replaced with an aluminum high-rise unit designed to flow freely and reduce weight. In place of the Autolite four-barrel carb, a Holley R3259 four-barrel unit was installed, featuring a flow capacity of 715 cfm. Finned aluminum valve covers and an extra-capacity aluminum oil pan were also included. The 289 found in the GT350 street version was rated at 306 hp, a 35hp gain over the stock K-code rating of 271. Also made during the '65 model year were about 36 racing versions, or R-models. These competition models were rated at up to 350 hp.