Help me out? Distributer (OSAC) Valve

The OSAC valve delays the change in ported vacuum to the distributor when transferring from idle to part throttle to reduce oxides of nitrogen. The OSAC valve is typically located on the air cleaner housing near the snorkle. The black tube from the carburetor is supposed to go on the fitting on the bottom of the OSAC valve. A red stripe tube is supposed to go from the OSAC to the vacuum advance on the distributor.

It is possible that the OSAC was by-passed by a tube directly from the carburetor to the distributor. If such a tube is present on your car, put a cap on the OSAC fitting on the carburetor if the car no longer needs to pass emissions testing.