Guys I have a Y-Block Mallory dual point up on EBAY. It has a vacuum port on the side and some sort of contact pad behind it. I've never seen one of these before. I was told that some of the Mallory's had a vacuum advance system. I'm wondering if it delays the mechanical advance until vacuum is up enough to pull the pad away from the advance plate. Total guess! Anyway take a look at my listing. I'd prefer to sell to one of the Y's guys if possible. Chuck
http://www.ebay.com/itm/332155733571?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649