If you're talking about the air lines that force air into the exhaust manifolds from the air pump, that is an emissions thing. You could buy headers that have the threaded ports in them, add them yourself to headers that you've already bought, or defeat the emissions controls completely (not legal). Can't think of any vacuum lines involved with headers.
from the vacuum source in the intake manifold,to various vacuum operated components
Vacuum lines installed correctly? Vacuum ports on carb. working?
these are on the front of the carburetor after the intake
any petcocks on the throttle body or intake are vacuum lines excluding fuel lines
engine vacuum or direct into the intake.
Most of the vaccumn lines are located on the engine itself around the intake.
There are more than 14 vacuum lines on the 1997 GMC. Most of the vacuum lines originate from the air intake system or the transmission.
Most all of the vacuum lines will start from the intake manifold in the rear..........
There are about 20 vacuum lines. Do you mean a main intake manifold line?
Vacuum leaks in the vacuum hoses or mixed up connections on them. Test by spraying starter fluid around intake manifold and vacuum lines.
The common issue is a vacuum leak. Check you vacuum lines and the rubber connectors that are on the intake runners.
Under the hood, they are plugged into the Intake plenum by the MAF.