One of my buddies brought his 82 over the other day to check a trans leak. Well, Two guys and a Corvette, ya gotta play as long as the wife will allow. We were checking his head llight actuators. He had just had them replaced and wondered why they were moving so slow and taking forever to open and close. I started checking the plumbing aginst the ones on my 77. Then I pulled a hose off to set it better and noticed that there wasn't much vacuum. I got out the ol gage and it was readying 6lbs of vacuum. I checked my vette and was getting 18. 18 is on the lower end of the green on the gage. I checked vacuum in different locations some from intake and some from carb base. even under acceleration, it never got over 12.  I haven't checked the compression yet, but low vacuum is a sign of low compression isn't it??