Thoroughly redesigned from stem to stern, the all-new trucks for 1973 proved to be the longest lived series in GMC’s history and is the one to have for fans of three-box styling. Aside from wheels and hubcaps, there aren’t many curves in the design, unless you count the body sides that feature a sculpted character line with a central plateau body panel and the first use of curved side glass on a GM truck.

This platform also featured GM’s first in-house built crew cab, along with the Suburban’s finally getting four doors like a normal station wagon. GMC also offered this cab with only a single front bench seat beginning in 1976 as the Bonus Cab, as something of a competitor to the Dodge Club Cab and Ford SuperCab.

Trim lines ranged from the entry level Custom, Custom Super, Sierra, to top end Sierra Grande. Names were revised in 1975, with the hierarchy going from Sierra, Sierra Grande, High Sierra, to Sierra Classic. This remained in effect through 1982, when the High Sierra was dropped, with the others continuing though the end of series production. 1975 also saw a one-year only “Gentleman Jim” package.

1980 had a one-year only front end, with a flatter front grille and square headlights. It proved to be a preview for 1981 and the rest of the production run, with an all new simplified front clip, new hood and single plane grille. Powertrains generally continued as before 1973, except that the 454 cid big block replaced the previous 402. In 1978, GM’s infamous 350 V-8 diesel pickup was introduced. 1982 saw a vastly improved 6.2-liter diesel introduced as its replacement.

The 1987 model year - the final year of production - saw the series designators changed. The two-wheel-drive C-series became the R-series, then the four-wheel-drive K-series was renamed the V-series. This was done to allow for concurrent production of its replacement early in 1987 of the all-new C and K models.