eBay
New Energy Suspension polyurethane sway bar bushing kit.  Kit includes bushings for rear sway bar and rear link bars (6 bushings).  Polyurethane bushings offer a firmer suspension vs the stock rubber bushings, for a performance feel.  Kit includes black bushings. Fits the following:

67-81 Firebird (all models) with 5/8" rear sway bar and a 2-bolt link bar (see inset photo)
67-81 Camaro (all models) with 5/8" rear sway bar and a 2-bolt link bar (see inset photo)

NOTE : Sway bars come in 8 diameters, and 2 different link bar setups, totaling 16 different kits.  It is EXTREMELY important that you take the time to measure your sway bar accurately, and identify which link bar you have on YOUR car.  Please review the inset photos we have included so you can properly measure your sway bar and identify which link bar you have.  The bushings are not interchangeable between the different bars!

INSTALLATION NOTE : Sway bar bushings slide over sway bar, upper link bars need to be pressed into the link bar, with a press or vice.