Vacuum range for 245 Six

Posted by Packard Newbie On 2021/1/22 21:03:01

I am going over a lot of 'small stuff' on my car this winter and one of the items on the to-do list was take the distributor out and lubricate the advance mechanism and confirm my Vacuum pot is functioning properly. I did this and found it made quite a difference with the way the counter-weights 'snapped back' after the vacuum was released as opposed to the slow movement prior to being serviced. Then I wanted to check the ACTUAL engine vacuum (I checked the dist. with a hand pump) so I hooked up a gauge to the intake manifold. With the engine running at a nice idle (+/-700RPM) the gauge registered right on the border of red and green, about 15/16 inches of vacuum. The engine is a fresh rebuild and has lots of power, any ideas why I wouldn't be up around 20 inches or so on the gauge?? The gauge also flutters ever so slightly and the performance card suggested bad plugs, so I replaced them. The old ones looked fine and all exactly the same. I haven't run the engine since I redid the plugs as we have had a cold snap suddenly and it's -15, so I don't want to even try. The gauge shows all the other functions as normal, i.e., when revved, it drops momentarily and then goes into the green for a sec and then back to the idle reading. Anyone have any thoughts re the 245 and what it SHOULD develop for 'normal' vacuum?? And am I checking it in the correct place by using the threaded hole in the intake or should I be reading off the carb?? I DID check that all nuts and bolts were snug on the manifolds, and it sure idles nice and revs responsively... Chris.