My first experience with the vacuum gauge timing wasn't a total success. I connected my vacuum gauge into the intake manifold where the wiper and Hydravac are normally connected. I did not disconnect the vacuum advance that connects to the carburetor. The Pertronix setup had already been completed and the truck cranked right up after it was installed. The vacuum reading on the gauge would never remain steady when the truck was running, idle or accelerated. It bounced like a ping pong ball from about 15-20 on the vacuum gauge but never stabilized at one point. I adjusted the distributor to try and get it to its maximum vacuum reading and then backed it back down a small amount. The truck ran well and seemed to have more power than its previously had. But re-cranking it while its hot was not happening. So I had to tinker with it to get it to restart.
What did I do wrong or what could cause the vacuum to be so erratic?
