Can you GAIN vacuum by eliminating vacuum driven stuff?
 

Ok, probably don't know what the hell I'm talking about...but I was just wondering, but does manifold vacuum at idle go up if you remove something that hogs some vacuum to work? The more vacuum driven accessories or devices you have, does that mean your vacuum will drop eventually?

Good question. It seems it would be that way logically, but I'm not for sure. Anyone? TED?

Only if something is leaking vacuum. Under various conditions the engine will pull certain amounts of vacuum which pulls equally against all the "users". Since the vacuum items are all static (unlike vacuum driven windshield wipers most of you aren't old enough to remember) will only happen if there's a leak.

PS-The old vacuum wipers came to a stop when the throttle was floored. Real pain in the behind. Very effective in a snowstorm when climbing the pass. :(