History of the Cobra Engine

the real deal: one of only a thousand or so genuine Shelby Cobras built. Except for the paint, everything in this specimen is original.       Figure A       The 289 cubic-inch engine, used in the earlier Cobras       Figure B

When you talk about speed. What Rolls is to "luxurious," Cobra. was to "fast." In fact, the Cobra was a beast. It was devastatingly, almighty fast: zero to 60 mph in about four-and-a-half seconds, and from zero to 100 mph and back to zero in less than 15 - with street tires. The car would literally launch. And that was in 1965. That kind of speed was enabled by some engineering smarts, a lightweight aluminum body and a very efficient V8 engine that  put fear in competitors like Ferrari, among others.

When you set out to build a Cobra replica, your initial - and perhaps your biggest -- decision will be what size engine to put in it. Consider the history of the Cobra engine.

The 260 and 289 Engines

The vintage Cobra shown in the demonstration is a 1963 model equipped with its original 289-cubic-inch engine (figure A). The very first Cobras, released in 1962, actually had 260-cubic-inch engines simply because that size was more readily available at the time. Only a few dozen cars were made using the 260 engine, however. Soon new Cobras began being fitted with the larger 289, which was actually a production engine -- used extensively in Ford's Falcon and Fairlane series. The 289 was an innovative engine for its time: small, lightweight and built with a thin-wall casting of high nickel content. It was designed for durability and for use in production cars, but the lightweight, rigid construction also made it suitable for racing applications. As it was tested and modified for racing, the engine continued to be improved and further developed. This engine later evolved into the 302 and 351w engines of today. Most of Engine Factory's customers opt for the 351w selection  for it's optimal  torque / power / handling characteristics. The 302 engine is an improvement from the 260 and 289 with the roller camshaft and full round 1 piece rear main cap seal.

About 650 Cobras were built using the 289 engine. Although most auto enthusiasts associate the Cobra with the famous 427 engine that would be used later, it was really the 289 that first established the car's reputation -- leading it to be a strong contender in racing championships in 1964 and then to become a dominant winner in 1965. Cobras equipped with the 289 would eventually beat seasoned European racing teams like Ferrari on their own ground, in Le Mans and at Nurburg Ring.

The 427 and 428 Engines

The 427-cubic-inch engine was developed for propelling big-bodied Fords around the oval tracks in NASCAR competition. Eventually the engine showed up in Ford's GT40 program. In 1965 Shelby's racing team decided that the Cobra needed more power on the long straightaways at Le Mans, and thus they began installing the big-block engine in the Cobra's lightweight frame. These days for practical purposes the 427 and 428 motor in a kit is not the ideal  choice for street driven car. They are a lot heavier, run hotter and cost a fortune to find and build. The cars handle a lot better with a small block 302 or 351w. The small block Fords can develop 500+ HP these days as well.

There was also the 428 engine. The 427 block (figure B) was designed as a race-only engine, and by the time Shelby began incorporating it, most of those built had already been dedicated to the racing program. To facilitate the building of a production version, Shelby began using a 428 engine, a production engine that was much cheaper and easier to obtain than the 427. The two engines were practically the same, and most parts were interchangeable, so Shelby began building street-version Cobras with the 428 -- the one found in most of the latter-day Cobras. The main difference between the racing 427 and the 428 was that the 427 was originally designed as a "top oiler" or "center oiler" -- a term that relates to how the oil flows through the crank. That's a brief  history of the Cobra engine. Enjoy the ride.

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