Just replaced the fuel pump on my 56 Super. When I took the old unit off there were no fittings or vacuum hoses on the lower vacuum pump portion. Now I have fittings and need to know how to hook up the input (vacuum) and output fittings. My manual gives hints but no diagram. Do I just hook the vacuum outlet to the manifold fitting in front of the carb? That seems logical. But where does the output go? The manual cryptically says back to the crankcase. But where?

Also, when I put a vacuum meter on the manifold fitting I get a wildly fluctuating needle. I suspect this is not good. Anybody know what that means? I did a compression check several years ago and the 97,000 mile original engine had pressures ranging from 120 to 150 with no two adjacent cyls the same.

Thanks in advance for any help.