I recently had my Holley four-barrel carburetor rebuilt and after reinstalling the darn thing I noticed the vacuum hose was loose. It's not the one that attaches from the distributor to the carburetor but the other, which I think might go to the transmission. If it does go to the transmission, where does it connect?

If it is the line to the transmission, it connects to the vacuum modulator. This is a small canister at the rear of the transmission case. It controls the up shifting of the transmission at part throttle.

What year Bird? Which motor?

I found the problem. It's not hooked up to anything. The problem was that a lifter was stuck and bent one of the push rods. Thanks.