What is a K-Code Ford Mustang?

Discover the K-Code Mustang

K-Code Engine
K-Code Engine. Photo © Jonathan P. Lamas

If you're a Ford Mustang enthusiast, you have probably heard other collectors talk about the K-Code Mustang. What was this coveted K-Code Mustang all about, and what made it so different from other models of its time? The K-Code Mustang was a special-edition Mustang made between 1965 and 1967 that came from the factory with a special 289 high-performance cubic-inch engine beneath its hood. In its day, it was quite a beast on the road.

All About the K-Code Ford Mustang Package

Buyers of the GT Equipment Package on their Mustangs could add the K-code option to their new ride for an extra $276 back in 1965. The cost to add this engine to new Mustangs without the GT package was $328. Why was it called "K-Code?" The “K” stood for the engine code on the VIN number of these Mustangs. The K-Code engine was first introduced by Ford in 1963 and was featured in cars such as the Fairlane and the Comet.

Each K-Code Mustang had a special badge on their front fenders that read “HIGH PERFORMANCE 289”. No doubt about it, the K-Code Mustang was all performance. In fact, K-Code Mustangs were not available with air conditioning or power steering. And you couldn’t buy one with an automatic transmission until the 1966 model year. Prior to that, the K-Code Mustangs had only four speeds. The car also came with a shorter warranty than the typical Mustang. K-Code buyers were looking at a three-month or 4,000-mile warranty instead of the standard 12-month or 12,000-mile warranty plan.

People often ask how the K-Code engine was different from the other 289 engines that fell under the D, C and A codes produced from 1965 to 1967 Mustangs. For starters, this engine featured upgraded pistons, cylinder heads, carburetor, lifter heads, and connecting rods. In addition, one look under the hood and you’d notice the chrome air cleaner and valve covers. There was also letting on top of the air cleaner that read " 289 High Performance."

Power Made the Difference in the Ford Mustang K-Code

With an estimated 271-hp engine on board, it was easy to tell this car from other 289 powered Mustangs of the day.

The differences didn’t stop there. In fact, the entire driveline of these cars was designed for performance. We’re talking about a high-performance clutch, drive shaft, rear differential, and suspension. It’s no wonder Shelby put the engine in his racing performance GT350 Mustangs. In fact, the first Shelby Mustang, the Shelby GT350R featured a modified K-Code engine.

These days, collectors of the Ford Mustang look back fondly on the K-Code. As such, these are highly sought-after Ford Mustang models and many collectors are on the hunt for them. Unfortunately, only a limited number of these engines were produced between 1963 to 1967, and there were even fewer K-code Mustangs (only about 13,214 were made). If you own one, you own a valued piece of Mustang history and have a prized classic car commodity on your hands. If you want one, join the club.