Tom, I saw somewhere on here you mentioned Cramac III, I e-mailed Craig some time ago about using Cramac III in our legend car and if I remember correctly he said they had run it in someones car for a season as a test with no clutch problems. As I said it was quite a while back. Maybe you could get in touch with him and have him post on here like he does on 4 cycle .com. The man knows his Oils.