Found the correct 1 1/2" dia Shackle bushings at Eaton Spring in Detroit.
Part Number HB830 5/8 x 1 1/2 x 1 1/4 x 1 3/4 Bushing $8.95 each
Also note that the Axle Isolator Pads they sell MUR1001 are shorter than the original Imperial pad.....They will fit the spring mounting hardware, but they...