I post this just to avoid any "confusion" on anyone's part. There is a 3 groove, cast iron crank pulley up for auction on eBay at the present time (eBay #4592138554). The seller claims that this pulley is applicable to Corvettes and Camaros. He's right about the Camaro part. This pulley was used on some 67-68 Camaros with SHP big blocks. It was also used on some 65-68 Chevelles, Chevy II's and full size passenger cars with SHP big blocks. However, it was NEVER, EVER used on ANY Corvette. I think that the seller just assumed that. However, the seller is incorrect.