Got a classic C3 Corvette (1963-1982) with a clunky, loose-feeling rear end? Upgrading to polyurethane bushings can make a huge difference. This kit from Corvette America is specifically for the differential front mount. It includes the polyurethane bushings you need to replace the old, worn-out rubber ones. Polyurethane is much stiffer than rubber, which reduces drivetrain movement, minimizes wheel hop during hard acceleration, and gives you a more connected, precise feel from the rear suspension. The trade-off is a slightly firmer ride and maybe a bit more noise/vibration – but that's part of the performance upgrade. Part number is 40598. It's a vintage part for a vintage car. No UPC. If you're restoring your Vette or just want to tighten up the handling, this is a popular and effective mod. Installation requires jacking up the rear, supporting the differential, and pressing out the old bushings. A straightforward job for a knowledgeable DIYer. Give your Stingray or Shark a solid foundation with these quality bushings.