In 1967, the Ford Motor Company initiated a program to develop a high-performance, 428-powered Mustang. Following research and testing, Ford unveiled their new high-performance street machine in April 1968 as the 428 Cobra Jet.
The Cobra Jet package featured a 428 short-block with police interceptor heavy-duty connecting rods, topped by 427 “low-riser” cylinder heads and a Holley 735 cfm four-barrel carburetor. With a claimed 10.6:1 compression ratio, the Cobra Jet utilized the same hydraulic camshaft as the 390 GT engine, known for its fairly aggressive grind at 270/290-degrees duration (advertised) and .481/.490-inch lift.
To acquire the 428 CJ engine, buyers had to opt for the GT equipment package, applicable to both coupe and fastback models. Power front disc brakes were mandatory, and purchasers could choose between the four-speed manual, as seen in this car, or the C-6 three-speed automatic.
Despite Ford’s modest rating of 335 hp for the new 428 CJ engine—only 15 more than the 390 it replaced—it appeared as a marginal improvement on paper. Given that buyers also had to select the GT package, disc brakes, and the engine, the Cobra Jet Mustang came with a relatively high cost. The mid-year introduction, coupled with these factors, likely contributed to only 1,299 examples being produced for the 1968 model year.
Source: RM Sotheby’s
