For 1974, a new rear bumper system replaced the squared tail and chrome rear bumper blades introduced in 1967 with a trim, tapering urethane cover carrying an integral license plate holder and recesses for the trademark round taillights. Underneath sat a box-section aluminum impact bar on two Omark-bolt slider brackets similar to the system used in the nose which allowed the Corvette to pass federal five-mph impact tests at the rear as well as the front. The new rear design was more up-to-date than the 60's shape that it replaced with the vast majority of enthusiasts embracing the new design. For the 1974 model only, casting limitations mandated left and right bumper covers with a vertical center seam. The anti-theft alarm key activator was moved from the rear panel to the front left fender. Tailpipes were now turned down as the new bumper cover eliminated the tailpipe extensions.