Lighter than the stock steel pulley, these pulleys are made in a permanent mold with 356 T6 aircraft quality aluminum molded over a steel center with 34 outer ribs to create a bond that will not come loose. Special features include hard anodized teeth for longer pulley and belt life and 2 tapped holes for easy removal. Each kit includes seal, pulley spacer and retaining plate. Made with a 3/4 inch wide spline and correct length spacer, these pulleys retro fit the 1985-early 1994 pulleys that only had a 7/10 inch wide spline and were notorious for working loose. Fits Big Twin 1985-later.