Will this work?
5XK88
Isolator,Vibration
Vibration Isolator, Maximum Load Downward Compression 460 Pounds, Maximum Load Sideways Shear 155 Pounds, Thread Size 3/8-16 Inch, Dimension A 2 1/2 Inches APPROVED VENDOR
5XK88 1 Today $7.45 1956
I found these on Grainger