UMI Performance 74-92 GM F-Body GM G-Body Frame Side Solid Engine MountsUMIs solid motor mounts replace the factory rubber motor mounts decreasing engine movement for maximal vehicle performance. Solid mounts bolt directly to the frame of the 1974 1992 Camaro Firebird and 1978 1988 GM G Body as well as many other 1974 and up GM V8 applications.. Solid mounts are required to be used in conjunction with factory block mount clamshells or UMIs P N 90058 clamshells. Note: Centerline is 1" from cross member surface to center of