Ford Mustang History (1970)
Article by Mark Trotta
Along with the upscale Mustang Grande, 1970 models included the Mach I, Boss 302 and the limited production Boss 429. Three body styles were produced; hardtop, convertible, and fastback (SportsRoof).
A minor re-design of the popular 1969 Mustang included a lower, wider grille and a return to dual headlamps. In the center of the grille was a red, white and blue striped pony emblem. Simulated air scoops were added outboard of the headlamps. Other exterior changes included a revised rear tail-lamp panel, now flat instead of concave as seen on previous models.
The 1970 Mustang's frame and wheelbase remained the same at 108 inches, but total length grew from 181 inches to 183.6 inches. Length and width also increased.
Front suspension continued with independent coil springs and an anti-roll bar. A solid rear axle, available in several gear ratios, was attached by semi-elliptical rear leaf springs.
Introduced in 1969, the Mustang Grande was again offered only as a hardtop. Standard items included a vinyl top, exterior striping and additional exterior moldings, full wheel covers, and color-keyed racing mirrors.
The Mustang Grande interior included luxury trim bucket seats, deluxe two-spoke steering wheel, and additional sound insulation.
Base engine for the 1970 Mustang convertible and Grande models was Ford's overhead valve 200ci six-cylinder, producing 115 horsepower. Optional V8 choices included the 302 and 351 Windsor small blocks, and 351 Cleveland, 428, and 429 big-blocks.
The 302 V8 with two-barrel carburetor produced 220 horsepower, while with the four-barrel 302 produced 290 horsepower.
351 Cleveland V8
New for 1970 was the 351 cubic-inch 'Cleveland' V8 engine, in two-barrel and four-barrel configurations. The two-barrel version was rated at 250 horsepower, while the four-barrel brought horsepower to 300.
428 CobraJet V8
The 428ci CobraJet engine continued unchanged from 1969. Although advertised at just 335 horsepower, in reality engine output was closer to 400 horsepower. The 428 Super CobraJet had a higher compression ratio and was rated at 360 horsepower from the factory (actual horsepower was higher).
Read: Top Five Muscle Car Engines
1970 Mustang Mach I
Introduced a year before, the popular Mach I trim level package included vinyl bucket seats, hood scoop, color-keyed racing mirrors, deluxe steering wheel with rim-blow feature, rocker panel moldings, console-mounted shifter.
Base engine for the 1970 Mach I was a 351 two-barrel V8. Optional were 351 with four-barrel, 428, and 429 big-block engines.
Mustang GT Discontinued
With only 5,396 GT models sold in 1969, the discontinuance of the Mustang GT was certainly due to the success of the new Mach 1. The GT would not return to the Mustang lineup until 1982.
Trans Am Series
SCCA Trans-Am racing was very popular in the mid sixties and early seventies. There were two engine classes; "Under 2.0 Litre" (European cars) and "Over 2.0 Litre" (American cars). Engines in the latter category could be no larger than 5.0 litres (305 cubic-inches).
1970 Mustang Boss 302
The Boss 302 was purpose-built to have Mustangs eligible for SCCA Trans-Am racing. Most of the 302's power was due to the large-port, large-valve, free-flowing heads. Along with a high-lift mechanical cam, the bottom end included a forged steel crankshaft, heavy-duty connecting rods, and forged pistons.
Since insurance companies charged a premium to cover high-horsepower engines, car manufacturers purposely underrated performance engines. The official factory rating for the 302 was 290 horsepower, but actual horsepower of the high-revving small-block was much higher.
Available only as a fastback, the Boss 302 featured quick-ratio steering and upgraded brakes and suspension. The exterior featured a front chin spoiler and blacked-out hood, trunk lid and taillight panel. A rear spoiler and rear window louvers could be added at extra cost.
The Boss 302 was not in the standard sales brochure, and only 1,628 were built.
1970 Mustang Boss 429
The Boss 429 first appeared in mid 1969, and then offered again in 1970.
The 429ci engine was physically bigger than all previous V8's - so much so that the Mustang's suspension had to be modified to fit it. It did not fit under a stock hood, and a hood scoop was placed on all Mustangs so equipped. The "shaker" scoop was mounted to the motor and stuck out of a cutout in the hood. To save space and weight, the battery was moved to the trunk.
1970 Mustang Production
Total production for the 1970 Ford Mustang was 197,045 units, significantly lower than the prior year's 299,824 units.