The Mustang was restyled for 1969, gaining 3.8 inches of length, all ahead of the front wheels, and about 140 lbs in curb weight. The Mach 1 body style debuted in 1969 and came standard with a 351 cid V8 but could also be had with the 428 Cobra Jet, which now came in three states of tune. The first was a non-Ram Air version, followed by the Ram-Air version which breathed through a shaker hood scoop. Topping the list was the new Super Cobra Jet which came with the Drag Pack option. The Super Cobra Jet used the shaker hood scoop, a modified crankshaft and stronger connecting rods. The Drag Pack also came with limited-slip 3.91:1 or 4.30:1 rear axles and no air conditioning. All three engines were underrated at 335bhp. All this power overwhelmed the rear tires, which suffered from a 59/41% f/r bias which also hurt handling. But then, these Mustangs weren’t built for curves, just straight 1/4 mile lines.
The circle tracks were reserved for the Boss series of Mustangs. Named after stylist Larry Shinoda’s nickname for Ford president Semon “Bunkie” Knudson, the Boss Mustangs were built to qualify the 429 V8 for NASCAR. The Boss 429 package came with a race ready 429 cid V8 with ram air induction, an aluminum high riser and header type exhaust manifolds. Mandatory options included a four speed manual and a 3.91:1 Traction-Lok axle. Also included were an oil cooler, trunk mounted battery, race suspension, and the best interior Mustang had to offer. Although impressive on paper, the Boss 429s failed on the street where their dependence on high revs hurt their street starts and the initial batch had incorrect valve springs that would stop winding at 4500rpm instead of 6000rpm. Nevertheless, it had good handling and would last through 1970. To combat Chevrolet’s Camaro Z/28 in Trans Am racing, Ford built the Boss 302 which used a 302 cid V8 treated to the cylinder heads from the racing 351 cid engine and Ford’s largest carb. It was underrated at the same 290bhp as the Camaro Z/28’s engine and was available with the shaker hood scoop. Shelby Mustangs were still available, though they were more luxury oriented then ever before.
Production: Mach 1: 72,458 Convertible: 14,746 Grande Hardtop Coupe: 22,182 Boss 302: 1,934 Boss 429: 858
Engines: 200 I6 115 bhp. 250 I6 155 bhp. 302 V8 220 bhp. (Boss 302) 302 V8 290 bhp @ 5800 rpm, 290 lb-ft @ 4300 rpm. 351 V8 250 bhp. (All Cobra Jets) 428 V8 335 bhp @ 5200 rpm, 440 lb-ft @ 3400 rpm. (Boss 429) 429 V8 375 bhp @ 5200 rpm, 450 lb-ft @ 3400 rpm.
Performance: (Super Cobra Jet) 428/335: 0-60 in 5.7 sec, 1/4 mile in 13.9 sec @ 103mph. (Boss 429) 429/375: 0-60 in 6.8 sec, 1/4 mile in 14.0 sec @ 103mph.