[11toe]

i am currently rebuilding a 61 impala. and i have two dumb questions 1. i am changing the carb from 2 bbl to 4 bbl and need to know where to hook up the distributer vacumm advance i have a carb mounting post with a hollow stud and i think it goes there. 2. in the front driver side there is a black box with a vacumm hose coming out and running behind the master cylinder but no hooked up to anything where does it go and what is it for???

[jimfulco]

I'm not sure what you're dealing with, but the vacuum advance should be hooked up to a source that has vacuum when the motor is idling. What type of carb are you using?

[curtis73]

Agreed. Your hollow stud should be a manifold vacuum, but there are a couple other ports on the carb that will work. There is usually a big port in the plenum behind the carb, and depending on the carb there are often one or two on the front.

You can get it running without the vacuum advance on (but you'll probably have to advance the timing a bit. Then you can pull caps off of ports on the carb and use your finger or ear to see if there is vacuum at the port at idle. If vacuum only shows up when you crack the throttle, then its ported or venturi vacuum and should stay capped.

You can also often use deductive reasoning. If you turn the carb over there are little passages that would be open to the manifold all the time. Sometimes there is a port directly above or near one of those passages.