4-jaw; You sound like the guy who can answer a question I have had for years. I have called radio 'expert' mechanics and they him-haw around and have no answer. When do you use manifold vacuum and when do you use ported vacuum to power vacuum advance mechanisms? They do their job at very different times in engine operation.
[ August 12, 2002: Message edited by: firstname.lastname@example.org ]</p>