The Specifications & Date of Manufacture for a 1955 GMC Pickupby Marlin Quintana
1955 was an unusual year in the history of GMC (and Chevrolet) light trucks. Initially, the trucks were much the same as in '54, but at mid-year the company introduced a new generation, featuring updated lines with a scalloped hood, wraparound windshield, hooded headlights and other changes. The first group of trucks, known as the First Series, was produced until the Second Series debuted on March 25, 1955. Besides styling changes, the new trucks saw the addition of a V-8 engine option and the switch to a 12-volt electrical system.
Body Styles and Dimensions
The 1/2-ton 100 series was available as a chassis-and-cab, pickup, panel truck and Suburban. The canopy truck, similar to a panel truck but with open sides at the back, was offered with the First Series, but didn't make it beyond that. Short and long beds in the First Series had wheelbases of 116 and 125.25 inches respectively, while in the Second Series they had wheelbases of 114 and 123.25 inches. Suburbans and panel trucks were available only with the short wheelbase, while a stake truck was offered with the long wheelbase only. The Second Series saw the debut of the Suburban Pickup, a well-trimmed version of the short-wheelbase pickup. The 3/4-ton 150 series was available as chassis-and-cab, pickup and stake truck in the same long wheelbase: 125.25 inches in the First Series, 123.25 in the Second Series. It was also offered as a chassis only in wheelbases of 104, 125 and 137 inches. The 1-ton 250 series came with a wheelbase of 137 inches (First Series) or 135 inches (Second Series) in a variety of styles: chassis-and-cab, stake, platform, pickup (Second Series), panel and canopy (First Series). It was also offered as a chassis-and-cab with a 125.25-inch wheelbase in the First Series, and a 114- or 123.25-inch wheelbase in the Second Series. Curb weights depend on body style and engine. A Second Series short-wheelbase 1/2-ton pickup weighs 3,375 lbs. with the six-cylinder, while a 3/4-ton long-wheelbase pickup with the six weighs 3,750 lbs. Carrying capacity is specified by gross vehicle weight (GVW) ratings. For the Second Series 1/2-tons, GVW is rated at 5,000 lbs.; for 3/4-tons, it is 6,500 lbs.; for 1-tons, it is 8,800 lbs.
GMC continued to offer its 248-cubic-inch (4.1-liter) inline six as the base engine for both series. Featuring a 7.5 to 1 compression ratio and a Holley one-barrel carb, this powerplant produced 125 horsepower (hp) at 3,600 rpm and 214 foot-pounds of torque at 1,550 rpm. Introduced with the Second Series was Pontiac's new 287-cubic-inch (4.7-liter) V-8, which featured hydraulic valve lifters and a Carter or Rochester two-barrel carb. Running with a compression ratio of 7.4 to 1, it produced 155 hp and 246 foot-pounds of torque. A three-speed manual synchromesh with column-mounted shifter was the standard transmission. A four-speed manual was standard for 1-ton trucks, optional for 1/2-tons. A four-speed automatic was also an option.
All trucks featured four-wheel hydraulic drum brakes. 1/2-ton trucks had a semi-floating rear axle while others used a full-floating design. Power steering, a heavy-duty suspension, chrome bumpers and trim, heater/defroster and tinted glass were options. In the Second Series, a panoramic rear window, standard on the Suburban Pickup, was another option.
- "Standard Catalog of American Light-Duty Trucks, 2nd ed."; John Gunnell; 1993
- Hemmings Motor News: 1955 GMC 100