[JR.]

Unless you're talking Mustangs, where the K-code is the ORIGINAL 289ci V8 hi-po Muzzy and the basis of the original Shelby cars...


This is an excerpt from the Edmunds Mustang history on hipomustang.com

Ford's Mustang was conceived in full knowledge that in the mid-'60s the biggest population bubble in history was coming of age in America. Baby boomers would rule the '60s and there was little reason to think they wanted cars that were anything like their parents' cars. The production Mustang was shown to the public for the first time inside the Ford Pavilion at the New York World's Fair on April 17, 1964 — two months and nine days after the Beatles first came to New York to appear on The Ed Sullivan Show. It went on sale at Ford dealers that same day.

To make the Mustang affordable it needed to share much of its engineering with an existing Ford product. That product was the smallest Ford of the time, the compact Falcon. In fact, the first Mustangs were built in the same Dearborn, Mich., plant as the Falcon.

Initially offered as either a notchback coupe or convertible, the Mustang's unibody structure was laid over a 108-inch wheelbase and stretched out 181.6 inches from bumper to bumper. While it shared its front double-wishbone/coil spring and leaf spring rear suspension as well as its overall length with the Falcon, the proportions of the Mustang were different. Its cockpit was pushed further back on the chassis, resulting in a longer hood and shorter rear deck design, and both its roof and cowl were lower. It's with those proportions — detailed with such iconic touches as the running horse in the grille, the side scallops along the flanks and the taillights divided into three sections — the Mustang became a car people were instantly passionate about.

Engine choices started with the utterly lame 170-cubic-inch (2.8-liter) OHV straight six that made just 101 horsepower; then proceeded through a 200-cubic-inch (3.3-liter) OHV straight six rated at a flaccid 116 horsepower; a 260-cubic-inch (4.3-liter) OHV V8 breathing through a two-barrel carburetor and making 164 horsepower; a 210-horsepower two-barrel-equipped 289-cubic-inch (4.7-liter) V8; a four-barrel 289 making 220 horsepower; and, at the top, the famous 'K-code' high-compression, solid-lifter, four-barrel 289 pumping out a lusty 271 horsepower. K-code-equipped cars got a special badge on their front fenders indicating that not only did the engine displace 289 cubic inches, but that it was also the 'High Performance' version.

A three-speed manual transmission was standard with every engine except the 271-horse 289, which was available only with the four-speed manual that was optional on other models. The Cruise-O-Matic three-speed automatic transmission was also offered.

The three most significant additions to the Mustang for 1965 were the neat 2+2 fastback body, the optional GT equipment and trim package and optional power front disc brakes.

In order to go road racing head to head against Chevrolet's Corvette, Ford needed a two-seater. And rules said that Ford had to make at least 100 of them by January 1965. That's where Carroll Shelby came in.

Shelby, a Texan and longtime racer, saw the potential to slay Corvettes with the Mustang and took 100 of the first 2+2s equipped with the K-code engine built at Ford's San Jose, Calif., plant down to Los Angeles for modification into 'GT 350' models. Tossing the rear seats aside, Shelby added such performance items as oversize front disc brakes, a fiberglass hood and a lowered suspension with oversize tires on 15-inch wheels. Shelby's legendary series of modified Mustangs would be built through 1970 in various forms and are today considered some of the most desirable Mustangs ever built.