400 motor, Holley 750 vacuum secondary. If I pull the vacuum hose off the pcv, and the engine speeds up like crazy, could it be anything other than a vacuum leak? I put a vacuum gage on this connection and am getting 15" at idle.

Before, engine used to almost die out if I pulled the hose off the pcv, so I don't know why this is happening now. All I did is pull the carb off, check a few things and put it back together. I doublechecked and I didn't miss any vacuum connections. (No power brakes. Just the one vacuum fitting at the front of the carb plugged off).

Idle mixture too rich?

How does the driveability compare now to b 4? & you didn't change anything?, just pulled the carb to check it? What were you checking?

Only thing I did was go from 3/4 turn idle mixture to about 1 1/8 turn. I found a little binding somewhere was keeping the throttle open a little, so after I found the problem - I went back and richened it up. It's actually running better now.

So if pulling the pcv valve hose off makes a big rpm increase, guess I better start looking for a leak? Maybe I'll start by retorquing intake bolts on my relatively new Edelbrock Performer, and running a (unlit) propane torch around suspected leak areas.