I have a '66 Impala SS Convertible that I'm finally ready to put the body back on the frame. I originally bought a set of OER rubber bushings, then I bought some Poly bushings later after reading about the pros and cons. Anyway, both sets don't fit right. The Poly set (Prothane 7149) comes with 14 upper bushings, but no instructions. When I measured, positions 1, 2, and 7 (from the assembly manual) have 1 3/8" holes in the frame. Positions 3,4,5, and 6 have holes in the frame that are 1 3/16" diameter. With the Prothane kit, 8 of the upper bushings have boss diameters of 1 3/8" and three of them have boss diameters of 1 1/2". After seeing those, I opened the OER kit, and that kit also had boss diameters that were to large to install in the existing frame holes.
I see that many people have replaced the bushings, but I don't see many people discussing this issue. Does everybody just bore out the holes to make the new bushings fit? Any advice from somebody who's installed a kit on a 65 or 66 Impala, especially using the Prothane kit.