What Is the Shelby GT500 KR Police Interceptor?

“Shelby Mustang” and “police interceptor” aren’t generally words that go together. Usually we think of police interceptors as boxy Crown Victorias or, since 2012, late-model Tauruses. But for a brief period in time in the late ‘60s, the two actually shared a common engine.

Based on Ford’s famous FE platform, a modified police interceptor engine could be found in the 1967 Shelby GT500 and 1968 Shelby GT500KR, two of the most legendary pony cars of the classic era. Read on for a brief guide to the Shelby GT500 police interceptor engine.

Shelby GT500 KR Police Interceptor MustangAll About the FE Platform

The FE engine platform (short for Ford-Edsel) made up the bulk of Ford’s medium and big-block V8 offerings between 1958 and 1976. The FE engine features a Y-block design in which its cylinder casings carry on below the center line of the crank shaft, providing extra support for the engine bearings. For Mustang and Shelby fans, the two most notable iterations of the FE engine were the 427 and 428 — the latter of which also made an appearance on Ford’s police interceptor vehicles at the time.

The 428 Police Interceptor Engine

The 428 police interceptor engine could be found on both the 1967 Shelby GT500 and the 1968 GT500KR. Midway through the 1967 model year, the 427 was swapped out for a newer 428 Cobra Jet engine equipped with a Holley four-barrel carburetor.

The heavily modified engine ostensibly had a 335 horsepower rating, although it’s widely believed that number was deliberately underreported to avoid the higher rates insurers were charging at the time. Not only was the 428 faster, but it was also cheaper to produce, resulting in a true “performance car for the people.”

The 428’s Legacy

The 1968 Shelby GT500KR equipped with a Cobra Jet police interceptor engine was an immediate success on the track, claiming the title of “Super Stock Eliminator Champ” at the 1968 Winternationals. Anyone in the market for a 1967 or 1968 Shelby GT500 should be prepared to dig deep into their pocketbook — as one of the most sought-after performance variants of the first-gen Mustang, prices at auction regularly reach into the hundreds of thousands of dollars.