I believe this bracket and pulley is for a 1955 to 57 Chevrolet Corvette using a McCulloch supercharger. The part numbers cast into the bracket are C0-101-D 59 and on the pulley CH-7D 38470. Both the bracket and pulley are cast aluminum. The bracket does have a welded section next to a bolted on steel angle. There are lots of pictures so you can visualize this bracket and see the weld. The steel pulley on the idler arm has some pits. The crank pulley looks good.