Dave, If you're interested, I have this Billet pulley that I manufactured for my boat motor that I won't be using any more. It measures just under 6 11/16" OD and is designed, with the use of a larger than stock alt pulley, to slow down the alt. for high RPM's. I have $98 worth of Billet Aluminum and 8 hours of lathe time invested in it. I'll sell it for $200, with the Stainless bolts, and you pay the shipping from 99504 zip code.