Whiteline 1973 GMC Jimmy Complete Engine and Transmission Mount SetSoft factory bushings whilst they do a good job of not transmitting engine vibration, they do create vague and unresponsiveness in the vehicles drive train. Under hard acceleration, the engine and transmission rotates, Whiteline engine mount bushings work in conjunction with the OE rubber bushing giving your car better throttle response as well as more crisp and defined gear shifts. This Part Fits: Year Make Model Submodel 1978 GMC C35 Base 1978 GMC