When the opening in the core support was enlarged, the raised part of the core support was removed. A piece of 2x2 aluminum angle was used to provide a mounting place for the upper mounts. The upper mounts are a simple steel angle bracket that has a rubber gromet on one end. The bracket fits into a mating slot on the top tank of the radiator. The bracket is bolted through the aluminum angle stock.
The aluminum angle stock is bolted to the top of the remains of the core support.
This photo is of one of the top mounting brackets.