Year of manufacture1970
Max Larsen, Coldwater, Michigan (purchased new in 1970)
Michael Bolf, Plainwell, Michigan (acquired from the above in 1972)
Current Owner (acquired from the above)
Ford, seeking to improve its fortunes in NASCAR’s Grand National Division as the 1960s came to a close, developed a potent 429 cid V-8. The new engine featured four-bolt main bearing caps, a forged steel crankshaft, and large-valve aluminum cylinder heads with crescent-shaped combustion chambers. Required by homologation rules to offer at least 500 units in a regular production automobile, Ford placed the new V-8 in a restyled 1969 Mustang.
Dubbed the Mustang Boss 429 for its engine capacity and in a reference to Ford president Bunkie “Boss” Knudsen, the model featured a toned-down appearance with only a large hood scoop, NASCAR badge, and Boss 429 graphics. Final assembly was subcontracted to Kar Kraft, the legendary Ford Skunk Works, which modified the Mustang’s engine compartment and suspension to accept the big-block motor. Only 859 models were produced for 1969, and 499 for 1970.
Conservatively rated at 375 bhp and 450 lbs./ft. of torque, the Boss 429 channeled its power through a “Toploader” four-speed, close-ratio manual gearbox and 3.91:1 Traction-Lok rear axle. To resist flex during hard acceleration, diagonal braces were added between the wheelhouses and firewall. In April 1970, Motor Trend recorded the model’s 0–60 mph in 5.3 seconds, with the quarter-mile taking just 12.3 seconds at 112 mph.
According to a Marti Report and the original build sheet, which are included in the sale, this example was assembled at Ford’s Dearborn factory on October 13, 1969, before being shipped to Kar Kraft in Brighton, Michigan, for completion. Finished in the desirable color scheme of Grabber Green over White vinyl interior, this car was equipped with competition suspension, convenience package, power steering, power front disc brakes, AM radio, Rim Blow steering wheel, trunk-mounted battery, console, deluxe seat belts, tachometer, and electric clock.
Sold through Kimball Ford in Battle Creek, Michigan, to its first owner on May 19, 1970, this Boss 429 was acquired by Michael Bolf of Plainwell, Michigan, in September 1972, and remained in his ownership until being purchased by the current custodian in 2015. The consignor then sympathetically restored this Boss 429 from 2015 to 2017, employing Rob’s Corvette Center in Kalamazoo, Michigan, a facility known for its muscle-car restorations. During the process, factory-original features were retained wherever possible, and a file of invoices (totaling over $55,000) accompanies the sale.
Often referred to as the “Boss 9” by Blue Oval enthusiasts, the model cemented its reputation at the dragstrip a quarter-mile at a time. Coming from a limitedproduction run and offering ground-shaking power, this eye-catching Mustang Boss 429 would make a worthy addition to any muscle-car collection.