They feature a self-locking design that sandwiches the frame and holds it in position. This design eliminates noise that was associated with prior performance body mounts. They are especially recommended if you are installing a subframe connector. The concept of the subframe connector is to reduce chassis flex. Having all the bushings solid allows the subframe connector to do a better job.
Note: Going to a solid mount body bushing does not increase ride harshness. All you are doing is bolting a subframe solid to the body. This is no different then bolting a crossmember to a current uni-body car.
Six Interloc bushings are supplied with each kit. This includes two radiator core support and four main body bushings. Kits for use with Global West subframe connectors come with four bushings (two core support and two front body mounts). The rear two bushings come with the subframe connectors. New hardware is included.
Installation tip: The male portion of the mount goes between the body and frame. The female or cupped portion comes up from underneath and indexes over the step in the male bushing, sandwiching the frame.
Tech tip: Did you know that GM deleted all the body mounts on Camaro and Firebirds from 1982 to 2002. The cross-members are bolted directly to the body.