I recieved 2 Dayton 1L708 1 and 3/4 inch steel shaft collars from Grainger today. They fit the rear Monroe / Napa lower shock bodies perfectly....I'll be using them to install a pair of Sensa Track units this weekend. The options made available for rear shocks with these collars available in so many different sizes should be all you need to install Koni's KYB's etc.... Jim 6147 << 've done some more research. The big problem with rear shocks on the Delorean is the need for a collar to go around the lower shock body to support the lower coil spring seat. Well if you look in the current Grainger catalog on page 365 , you'll see two piece steel and stainless steel clamp style shaft collars. The Monroe Napa unit has a 1 and 3/4 inch lower shock body outside diameter. The clamp you can get from Grainger would be the 2 piece IL708 in steel or the 2 piece IL727 in stainless. >>