I recently replaced my vacuum advance because the diaphragm was blown and the truck was suffering from vacuum leak symptoms. Well, the new advance fixed my crappy idle and hard starts but...... /forums/images/graemlins/tongue.gif /forums/images/graemlins/mad.gif ......now I'm having pinging issues. I can't drop the timing much more because it's already set pretty low and I don't want to affect what little performance I'm getting out of the tired ol' 305. A buddy of mine recommended installing a "vacuum restrictor"(or something like that) because now I'm getting TOO much vacuum. If I'd known I would have had these issues I would have bought the adjustable vacuum advance model..... /forums/images/graemlins/rolleyes.gif Does anybody have a clue what he's talking about? What kind of vacuum readings should I be getting at the distributor anyhow?