Vacuum Gage(Gauge)

Close to the carb. The size of the line is not important as long as you don't get carried away. At some point, an oversize line may collapse. Too small a line will dampen the speed of the response at the gauge, which may be beneficial. A restrictor in the line will give the same result.

Thanks Tyrone for the info. Would on the PVC line but close to carb work? It's just easier to get at. I was wondering though that as the end of the line is open to whatever pressure is in the rocker cover, would that screw up the reading? Thanks again, Geoff

no

yes

The pcv is a controlled vacuum leak. You won't get a true reading of manifold vacuum there. Get right on the manifold somewhere.

Exactly. This is the correct answer you were looking for. Tee into something that's on the manifold. Stay away from the carburetor unless you don't have any choice at all. The a/c controls, if you have them, will be hooked onto the manifold. Power brakes also. Probably several other lines that run emissions equipment.

tee into the PB line BEFORE the check valve