Ford Mustang Cobra Jet

Mustang Cobra Jet at a glance

Tasca, Hot Rod and the 428

The Cobra Jet started at a dealership. Bob Tasca of Tasca Ford in Rhode Island built a 428-powered conversion he called KR-8, and in November 1967 Hot Rod writer Eric Dahlquist asked readers whether Ford should build a supercar Mustang on the Tasca formula. According to the NHRA, more than 20,000 ballots came back, and Ford dropped an earlier plan to use the 427.

Ford lent Dahlquist a white fastback for the first test. The March 1968 issue reported 13.56 s at 106.6 mph over the quarter mile, a figure autoevolution still lists among the quickest for any 428 Cobra Jet Ford. In Ford's 2008 press release, Tasca put it simply: "When I made the Cobra Jet engine available to Ford, they found out quickly how good it was."

The 135-series cars for the 1968 Winternationals

Before the regular option went on sale, Ford ordered 50 Wimbledon White Mustang GT fastbacks with the 428 Cobra Jet for drag racing. Their VINs run from 8F02R135007 to 8F02R135056, which is why collectors call them the 135-series cars. The NHRA dates the start of production to 13 December 1967, and Mustang Specs to a first batch of 18 scheduled for 30 December, so sources differ on the exact day.

To save weight, Ford left out the radio, sound deadener, undercoating and heater; every car had a black vinyl interior and a manual gearbox. Teams then added a 4.89:1 rear axle, roll bar, slicks and headers and moved the battery to the boot. At the Winternationals at Pomona in February 1968, Al Joniec in the Rice-Holman car beat Dave Wren's Plymouth in the Super Stock E final with 11.49 s at more than 120 mph.

The production 428 Cobra Jet

From April 1968 the Cobra Jet was built on the regular line. The 428 FE V8 used a 735 cfm Holley, heavier connecting rods with 13/32 in bolts and a nodular iron crankshaft. Ford's rating of 250 kW (335 hp) at 5,200 rpm sat close to the 390, and Wikipedia notes that period trap speeds suggested about 275 hp in SAE net terms.

In 1968 the same engine went into the Mercury Cougar, the Shelby GT500KR, the Fairlane and the Ford Torino. Autoevolution counts 1,299 Mustangs with the 428 Cobra Jet for 1968; Ford's own total is not in the sources used here, and the Cobra Jet registry refers owners to Marti production records for exact numbers.

Super Cobra Jet and the Drag Pack, 1969-1970

For 1969 and 1970 the Cobra Jet remained available in the Mustang, including the new Mach 1, and in the Cougar, later the basis of the Cougar Eliminator. The Super Cobra Jet shared the CJ's heads, camshaft, induction and block, but used:

• a stronger crankshaft (casting 1UA) with an external balance weight on the snout;
• heavier 427 "Le Mans" connecting rods with cap screws;
• slightly looser piston clearance for higher operating temperatures;
• an engine oil cooler.

The SCJ came with the Drag Pack, a 3.91:1 or 4.30:1 rear axle option, on cars built from 13 November 1968. Because the oil cooler took the space, these cars were never built with factory air conditioning. Ford kept the published rating at 250 kW (335 hp) and 597 Nm (440 lb-ft).

Cobra Jet as a factory drag car, 2008-2018

Forty years after the original, Ford Racing revealed the FR500CJ Cobra Jet at the SEMA Show on 4 November 2008. The initial run of 50 cars, all ordered by dealers, cost US$69,900 each in 2008. Built from base V6 Mustang bodies, they had a supercharged 5.4-litre V8 rated by Ford at 298 kW (400 hp) and weighed about 1,497 kg (3,300 lb); FordMuscle gives the NHRA factor as 425 hp, so figures vary. The first car left the Roush line in Livonia, Michigan, on 18 December 2008.

At the 2009 Winternationals John Calvert qualified second with 10.08 s, well under the 11.25 s A/Stock index, and won Stock Eliminator. Hagerty reports runs of 50 cars in 2010, 2012, 2013, 2014 and 2016. These Mustangs came without a VIN, so they could not be registered for road use.

For the 50th anniversary Ford announced 68 cars on 18 April 2018, in Race Red or Oxford White, with a supercharged 5.2-litre Coyote V8, an NHRA-certified roll cage and a Strange Engineering 9-inch solid axle. Ford claimed a quarter mile in the mid-8-second range at over 150 mph.

The electric Cobra Jet 1400 of 2020 was a one-off prototype. At its public debut at the NHRA U.S. Nationals in September 2020 Ford reported 8.27 s at 168 mph and 1,502 hp at the wheels in private testing.

Cobra Jet today: what to check

A 1968 Cobra Jet Mustang carries R as the engine letter in its VIN, and a 135-series car must fall inside the 8F02R135007 to 8F02R135056 range. A Super Cobra Jet should show the oil cooler, a 3.91 or 4.30 axle and no factory air conditioning. The 428 Cobra Jet Registry collects VINs, build dates, axle and transmission codes from 1968-1970 cars, and Marti Auto Works holds Ford's production records for 1967 to 1973. The modern drag cars have no VIN at all, which makes their build documents from Ford Performance the main proof of origin.

The Cobra Jet sits among Ford's other big-block cars in the American muscle car guide, and the wider family is covered in the Ford Mustang generations hub.