The second generation C/K Suburbans are easily recognised by having only a single drivers side door and two passenger-side doors. They were available in both 2WD and 4WD models. Engines included the V6 (e.g., Chevrolet 292-cubic-inch I6, and GMC 305 cubic inch V-6), and small-block V-8s of the current model year (e.g., 283, 307, 327, 350, 400-cubic-inch V-8s.) For the first time, a three-quarter ton version was available.
1971 saw the introduction of disc brakes on the front wheels, and 1972 was the last year for coil-spring rear suspension on 2WD models.
This series would also be the last to offer C-10 & C-20 Panel truck models for commercial purposes.
Source: Wikipedia, 2011