I have a vacuum loss at idle, when I increase throttle the vacuum goes up. It would appear that the loss of vacuum is coming from my vacuum advance on the distributor, when I plug it off i gain vacuum at idle.

im assuming this is wrong, as I’ve always been under the impression you should have the highest vacuum at idle. The vacuum advance shouldn’t take away vacuum should it?

any suggestions?

 

Suck on the port coming off the vacuum canister. If you stop it with your tongue and it doesn't maintain the vacuum, it's bad.