[Extract from:   The stuff legends are made of. By Dennis Begley]

In 1964, Carroll Shelby's A.C. Cobras dominated the American road racing scene. The Shelby American racing team and independent Cobras won every race they competed in. Shelby had intended the Cobras to be street cars and road racers. Ford wasn't interested in drag racing and therefore neither was Shelby American. Along the way, a few of Shelby's employees convinced him to furnish them a 289 Cobra to build a drag car. They called it the DragonSnake.

Cobras were ideal for modifying for the Strip. After all the whole car was a hybrid to start with. The all aluminium body was made at AC in England. The engineless AC's were shipped to the Shelby American in California to receive a Ford Hi-Po 289" - the first American factory to be in the engine swapping business. Prior to this time, if you wanted a V-8 powered sports car, you acquired a European car and put in your own American engine. The public loved the cars. The A.C. Cobra was an instant success. The drag racing public was accustomed to putting different, read that bigger, engines in cars for the drag strip. 

Almost every time the DragonSnake raced, it broke records. The driver, Jere Kirkpatrick, also maintained the chassis. Ralph Falconer, Jr., was responsible for the engines. Together they dominated the A/SP class. Top speed in the quarter for the 289 powered Cobra was 116.27 MPH in 11.81 seconds. 

The DragonSnake was modified for 1/4 mile racing. In the beginning the Cobra couldn't get traction even with a factory stock racing engine. All four wheels were independent, with springing by transverse semi-elliptic leaves. Weight transfer was the key to getting the right traction. Special drag strip Cure-Ride shocks with 50/50 control in the front and 90/10 in the rear that Up-Loc and Down-Loc on acceleration were installed. In order to maintain proper front end geometry during hard acceleration, the front springs were reformed down 2 1/2 " at the centreline and lengthened 5/16 " . The rear spring was lengthened .350" to prevent the axles from changing to a negative camber during acceleration. When the Cobra would leave the line, the body shifting backwards on the rear wheels  causing the tops of the tires to lean inward, reducing the tire surface area in contact with the ground. Those were the only changes made to the body of the sports car model.

Falconer came up with four engine combinations. All ended up being offered as options on the Cobra roadster. The first stage I-D, was 271 HP 289". The same engine with two four barrel carbs, rated at 300 HP, was stage 2. Swapping the two fours for four Italian Weber carbs, jumped the horse power to 325, stage 3, III-D. Each engine was carefully prepared to meet AHRA and NHRA standards. The last stage, IV-D, had the Webers, a special acceleration camshaft with ported and polished heads. Rated at 380 HP, the IV-D Cobras could only be raced in the AHRA sports car class.

Using a 4.89:1 rear end, the III-D Shelby Cobra outran everything on the drag strip, even the fuel injected big block 'Vettes.    

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