New Energy Suspension rear strut rod bushing kit.  This kit will do both strut bars, LH and RH.  This kit is polyurethane, which has less flex that rubber.  Bushings are black.  Fits the following:

75-82 Corvette w/ 1.75" OD strut bars

63-74 = 1.5" OD strut bars, 75-82 = 1.75" OD strut bars, check to ensure your rods were not replaced with a different year.