Blower Drive Service, Dyers, and Weiand are the first that come to mind. If you're looking for something bigger then a 6-71, then probably Mooneyham. Best to consult with the blower company you will be buying from before you make your selection on cam, pistons, and other components and go with their recomendations.... They will know what will live and what will make it a great big overpriced gernade!!!!!