This is the adapter you need to make. it's .25" thick aluminum with a total length of 4.5" I have anodized it flat black which I did myself first time in my garage. A=1.5" B= 2.1/8" C=3/8" D=2 3/8" E=3/4" The two holes I got as a template from positioning the original rectangular clamp piece at E as they are off center the first 1/8" hole is 5/8" from E and 7/16" from D they are 7/8" apart.