1966 Ford Mustang K Code Convertible

Year: 1966

Make: Ford

Model: Mustang

Type: Convertible

Details: Factory K Code

Engine: 289HiPo V8

Transmission: 4-Speed Manual


Stock#: 1781

Price: $89,000/Offer

This is a 1966 Ford mustang convertible factory k-code with a 289 Hi-Po motor, 4-speed, GT package and air conditioning!

Every once in a blue moon you come across a car that is what would be considered the holy Grail of that specific model. In this case we are talking about a car where Ford built only built perhaps 100 in 1966. This car is more rare than any 1966 Shelby Mustangs built. Out of those 100 or so cars, most were fastbacks and coupes and very (very) few were convertibles. This is one of those cars.

This is a factory built Mustang convertible matching numbers K code, 4-speed, GT package, and air-conditioning. The car has been sitting for the last 15 years and has recently been purchased from an estate, fully serviced by our shop and is ready for the next owner.

This is truly an amazing and rare opportunity to find an all matching numbers K-code car. Original door data tag and 25 years in the k-code registry show this car to be a survivor with one repaint. A nice driver indeed!

One of the most rare and most desirable of all mustangs, including the Shelby’s, this factory correct convertible is equipped with the legendary high performance 289 K code V8 and 4-speed makes this one of the most unusual and rare HiPo in existence. 

The K-code high-performance engine, known as the (HiPo 289) was first introduced in 1963, and it found its way into the Fairlane and Comet.

Carroll Shelby knew that the spunky V8 was the perfect engine for his new 1965 GT350, and the good folks at Ford were happy to oblige. Ford wanted the Shelbys to dominate the track and street, which only served to energize the Mustang mystique. Ford also wanted Mustang buyers to check the rambunctious, solid-lifter “K” engine as an option for any of the Mustang body styles — the humble coupe, racy fastback or sporty convertible.


Out of the box, the K-code 289 made 271 horsepower (306 in the modified Shelbys) — ever so near the one-horsepower-per-cubic-inch milestone that Chevrolet hyped so much. The K-code 289 made its power without the help of a supercharger or fuel injection.

This engine was Fords best naturally aspirated small block, and it simply pumped out the ponies effortlessly, with plenty of torque and throttle response. Even today, the K-code engine is noted as one of Fords most illustrious achievements. 

The Mustang enjoyed a sales curve that most automotive CEOs would envy — especially today. However, the K-code Mustangs never sold at the same pace as other V8 models. The power plants available in the 1965 through 1967 models were plentiful enough that most buyers simply did not check off the somewhat pricey K-code as an engine option.

As it was, the 289 engines came in the C-code 2-barrel carb and the A-code 4-barrel carb. Most buyers simply ordered (or purchased off the showroom floor) the 4-barrel-optioned 289 if they were seeking a more thrilling driving experience. By 1967, Mustang buyers could opt for the big-block 390.

So amid all the hype and excitement over big-block horsepower offered in all the American muscle cars, the 390-ci engines ended the HiPo 289’s run in the Mustang.

In total, it is thought that only 13,231 K-code Mustangs rolled off the line from 1965 through 1967 (for all years and body styles). There is no specific breakdown for total K-code production by body style until 1967. While 13,231 cars may sound like a lot, it’s actually quite low compared with the nearly 1.7 million Mustangs sold through 1967. By the breakdown, Ford sold 7,273 in 1965, 5,469 in 1966 and a paltry 489 in 1967. The number of K-code convertibles produced is widely agreed to be staggeringly low. Less than 1% of 1% of convertible production!

Part of the reason for the added expense of the K-code HiPo option dug much deeper than just an engine swap.

Ford knew these cars would be pushed hard. Buyers who opted for the 271 horses didn’t plan on using their car to drop the kids off at school. All sorts of parts were upgraded for the added stress of pedal mashing and tire smoking.

The engine flew under its own specs — as did much of the suspension, clutch (it could not be ordered with an automatic transmission until 1966), 4-speed, driveshaft, differential and other under-the-hood goodies. The K-code car was really its own Mustang model — which translates to a very special (and rare) Mustang today.

Separating the rare from the rarest

Finding a K-code Mustang for sale is not all that hard. With an effortless click of a few keys, I jumped online and noted over 7 for sale. And, as expected, most are coupes, with a few fastbacks sprinkled in. On the other hand, I found only two K-code convertibles. Both listed “inquire” instead of an asking price.

The fact that one didn’t need to order a GT model to add the K-code option adds to the value dynamic. So the rarity of this car increases, as it is a GT build from the factory. Keep digging, and you’ll soon learn that finding a K-code GT convertible for sale is very, very difficult.

Pushing all the buttons

At the end of this long and winding road, our subject car pushes a bunch of the right buttons — far more than most others that simply have a “K” in the VIN.


  • K-Code GT Convertible factory 4-speed air conditioning

  • Recent full bumper-to-bumper service - all fluids drained, systems flushed and all operating systems serviced

  • original carburetor rebuilt

  • new master cylinder

  • In the k-code registry

  • Very highly optioned

  • K-Code 289/271 HP solid lifter V-8 engine

  • 4-speed transmission

  • documented

  • original door tag

  • AM radio

  • Styled steel wheels

  • 25-year-old paint needs hood-damaged fixed

  • Candy apple Red with Red pony interior

  • White soft top needs a new rear window

  • Full length console

  • Pony interior

  • Flasher switch in the glove box

Fly in and drive home