The second generation K5 models made the rear hatch glass and tailgate into a single unit. This allowed the glass panel to retract inside the tailgate. It used either a manual handle or an electric motor to raise and lower the glass. For better fuel economy second generation Blazers used the smaller displacement 305 V-8. These engines produced nearly as much torque as the 350 V-8. However, these engines were not as powerful and prone to detonation (engine knocking). After 1987, when throttle-body injection was introduced in the truck engines, the 350 was made the standard engine.