I got a little crazy and ended up getting the two types listed above. I have 1/4" mounting holes in my brackets, the brackets are originals. The McMaster bumpers are for a 1/8" mounting hole. The part number is 9310K124. Fit is a little loose but all the rest is the same as the original. The other that I tried from the link above is a little taller but the fit is good. That one I found to be a GM trunk bumper/stop. The part number from OER is 4721222. That is available from many auto restoration companies, also Summit racing and Jegs. I am going with the McMasters and will use a dab of silicone to help hold them tight.

