The Prothane rear spring and shackle bushing kit for 1981–1987 GM rear suspensions includes 1.375-inch (1 3/8in) bushings in red polyurethane to replace aging rubber components. It helps restore spring alignment and reduces unwanted movement in the rear suspension. This kit is specified for GM rear spring and shackle setups from 1981 through 1987 and lists the bushing diameter as 1 3/8 inches.
Prothane 81-87 GM Rear Spring & Shackle Bushings (w/ 1 3/8in Bushings) - Red