1970 Ford Mustang Boss 429
8-cyl. 429cid/375hp 4bbl
With an experienced team and a lot of data.
The 1969 range was such a huge change for the Mustang that 1970 alterations were relatively minor. The four headlights were reduced to two seven-inch lights in the wider grille, with dummy intake where the outer lights had been. Fake intakes on the rear fenders of the fastbacks were deleted and the tail panel flattened, instead of concave.
Mustang Mach 1 models received rocker panels with the name stamped in, and honeycomb rear panel between the taillights, a black striped hood with a fake air intake. Hood clips replaced pins and a shaker hood was available with the 351 cid V-8. The GT package disappeared, but the Grande package returned with a half vinyl roof and hound’s tooth cloth seats. All Mustangs had high-back bucket seats.
Henry Ford fired Bunkie Knudsen in August, either because he wanted to move away from muscle cars or because Knudsen had been too successful in pushing the expanded performance range. In any event, sales dropped 100,000 units, largely because of competition from Chrysler in the form of the new Challenger and ‘Cuda as well as the redesigned Firebird and Camaro from GM. Total output for the year was 190,727 Mustangs, with 82,569 hardtops, 13,581 Grande hardtops, 45,934 fastbacks, 40,970 Mach 1s and only 7,673 convertibles. Prices began at $2,721 for the hardtop, $2,926 for the Grande, $2,771 for the fastback, $3,271 for the Mach 1 and $3,025 for the convertible.
Engines ranged from the 155 bhp 250 cid 6 six, through the 220 bhp 302 cid V-8, 250 bhp 351 cid V-8, 300 bhp, 351 cid V-8, 335 bhp 428 cid Cobra V-8, 335 bhp 428 cid Ram Air Cobra V-8 and the 375 bhp 429 cid V-8, which added an eye-watering $1,208 extra cost.
The Boss 302 Mustang continued to be enormously successful, with 6,318 sold, largely due to the popularity of the Trans Am racing series. The Boss 302 was a remarkable performer and the claimed 290 bhp is considered to be artificially low. Boss 302s had 4-speeds, disc brakes, sway bars and staggered shocks. Power steering was optional but helped the quick-steering box. The engine had a forged crank with four-bolt main bearings, forged connecting rods and a high-rise alloy intake to the Holley carburetor. A 5,800 rpm limit could safely be exceeded, and race engines reported up to 8,000 rpm. A shaker hood was optional, along with rear deck spoiler and rear louvers. The dual exhaust system was improved for both Boss models. At $3,720 the Boss 302 was a bargain, but this would be its last year.
The Boss 429 continued as Ford wanted to keep the engine homologated for NASCAR. A total of 499 were sold for 1970, built by Kar Kraft in Brighton Michigan, which heavily modified the front end, pushing the shock towers apart and fitting modified steering and unique front spindles. The Boss 429 was not available with automatic transmission or air conditioning, and the price was an intimidating $4,932. The estimated 375 bhp was considered to be about 100 bhp low. This would be the pinnacle of factory street performance for about 20 years.
A total of 16 colors were offered in 1970. Here are the codes: Raven Black (A); Dark Ivy Green Metallic (C), Yellow (D), Medium Lime Metallic G); Grabber Blue (J); Bright Gold Metallic(K); Wimbledon White (M); Pastel Blue (N); Medium Blue Metallic (Q); Medium Gold Metallic (S); Red (T); Grabber Orange (U); Grabber Green (Z); Calypso Coral (1); Light Ivy Yellow (2); Silver Blue Metallic (6). There were 29 interior combinations, and convertible tops were black or white.
Boss colors were Grabber Blue, Grabber Orange, Grabber Green Pastel Blue, and Calypso Coral, though there is evidence of Medium Lime Green and Medium Blue Metallic and occasional other colors as well. Interiors were black.