GM Truck Generations: The 1967-1972 "Action Line" Series


GM Truck Generations: The 1967-1972 "Action Line" Series


Introduction To The "Action Line" Series

1967 chevrolet truck advertisement

A new, more modern look for General Motors pickup truck line came in 1967, along with a new nickname: “Action Line”. The second-generation of the C/K truck saw General Motors begin to add comfort and convenience items to a vehicle line that had previously been for work purposes alone. Updated styling features for the 1967 model year trucks came with new sheet metal that helped to fight rust and a pickup box made of double-walled steel, both for Fleetside and Stepside beds. The majority of 10 and 20 series Chevrolet trucks from 1967 to 1972 were built with a coil spring trailing arm rear suspension, which greatly improved the ride over traditional leaf springs. However, the leaf spring rear suspension was still available on those trucks and standard on 30 series trucks. The front suspension on all Chevrolet trucks was independent front suspension with coil springs. GMC models came standard with leaf springs with coils springs optional; all four-wheel-drive models (Chevrolet and GMC) had leaf springs on both axles.

New For 1967...

1967 Chevrolet small back window

1967 was the only year for the “small rear window” (RPO A10 offered a large rear window as a factory option). The standard drivetrain came with a three-speed manual transmission and one of two engines; the 250ci "High Torque" straight six or the 283ci (4.6 L) V8. GMC trucks featured a unique engine option, the 60-degree big-block 305ci GMC V6. Four-speed manual transmissions, the two-speed Powerglide automatic and three-speed TH-350 and TH-400 automatic transmissions were optional, as were the 292ci six and the 327ci V8 were the optional engines. The 1/2 ton trucks came with a 6 x 5.5″ bolt pattern, while the 3/4 and 1-ton trucks came with an 8 x 6.5″ bolt pattern.

Model Year 1968 Updates

1968 GMC advertisment

The 283ci (4.6 L) V8 was replaced with a 307ci (5.0 L) engine and a 310 horsepower version of the Mark IV 396ci (6.5 L) V8 was offered for the first time. The most visible change used to tell the difference between a 1968 from a 1967 was the addition of side-marker reflectors on all fenders, a new requirement from the Department of Transportation. The small rear window was no longer available. The GMC grille was revised, with the letters “GMC” no longer embossed in the horizontal crossbar. A new addition was the Custom Comfort and Convenience interior package that fell between the Standard cab and CST cab options. In 1968, Chevrolet celebrated fifty years of truck manufacturing, and to commemorate it, they released a 50th Anniversary package, which featured an exclusive white-gold-white paint scheme. Additionally, the Longhorn model debuted on 3/4 ton trucks. Featuring a 133″ wheelbase identical to the one-ton vehicles, it added an extra six inches to the bed. Longhorn models, interestingly, were two-wheel-drive only; no factory Longhorn 4×4 was built.

Model Year 1969 Updates

1969 Chevrolet Blazer press release image

The 327ci V8 engine was enlarged in 1969 to 350ci (the piston stroke was increased from 3.25 to 3.48 inches), with horsepower ratings up to 255 horsepower. Along with the new engines came a new grille design for Chevrolet trucks and a more upright hood for both Chevrolet and GMC trucks. A utility variant, known as the K5 Blazer, joined the pickup truck and Suburban line. Along with it's GMC Jimmy twin, these new utility vehicles were introduced with a shorter wheelbase of 104 inches (2,642 mm). Some internal cab changes were also made, most notably the switch from a hand-operated parking brake to a foot pedal, and a more modern-looking two-spoke steering wheel with a plastic horn button replaced the previous year’s three-spoke wheel with a chrome horn button. Also new this year were upper and lower side moldings, which added another two-tone paint option. These were standard on CST trucks and optional in any other trim level.

Model Year 1970 Changes

1970 Chevrolet CST/10

The only noticeable change for 1970 was a minor update to the Chevrolet grille. At first glance, the 1969 and 1970 grilles appear identical. However, the 1970s plastic inserts actually have highlights that break the appearance into six separate sections. The 396, while still sold with that displacement used in advertisements, was enlarged to 402 cubic inches starting in 1970. The GMC V6 was phased out of the light truck market and relegated to medium and heavy-duty trucks from 1970 onwards.

Model Year 1971 Changes

1971 Suburban

Several changes occurred in 1971. First came another new grille design (the “egg-crate”) for Chevrolet trucks and black paint over portions of the GMC grille. Second, an additional trim package was introduced: the Cheyenne. On GMC models, this was referred to as the Sierra. These packages consisted mostly of comfort features — nicer interiors, more padding and insulation, carpet, chrome trim, and upper and lower side molding and tailgate trim. 1971 was the first year for AM/FM radios factory installed. Finally, the front brakes on all light-duty trucks were switched from drum brakes to disc brakes, resulting in much less brake fade under heavy use. While many prior C/K half-ton trucks had used a six-lug bolt pattern (6 x 5.5″) for the wheels, two-wheel-drive models switched to a five-lug pattern (5 x 5″ bolt circle) common to Buick, Oldsmobile, Pontiac, and Cadillac passenger cars. The 1/2 ton 4 x 4 retained the 6 lug bolt pattern. This bolt pattern would remain the standard through the end of the C/K series (along with the Chevrolet/GMC vans). Also, Chevrolet changed the 396 V8 emblem designation to 400 V8.

Model Year 1972 Changes

1972 GMC Stepside

The 1972 models were virtually identical to 1971 models, with the only change being the rear view mirror was glued to the windshield instead of being bolted to the top of the cab, and metal or vinyl-covered flat door panels were no longer available; all trim level door panels were molded plastic with integral armrests and wood grain inserts on Cheyenne and Sierra trim levels. For restoration, it should also be noted that the door and window cranks were slightly longer due to the molded plastic door panels, and the vent windows were now secured with a single screw on the inside of the door, thus differentiating it from the 1971 model year.


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