Vacuum Reducer Valve

This valve reduces vacuum by 11/2 inches Hg to prevent detonation when engine coolant is above 220° F and the DTVS ``MT'' is open to the distributor vacuum advance.
The VRV has one port on the manifold side and two ports on the DTVS side of the valve. The center port is open to vent at the carburetor air horn, and the outboard port to the ``MT'' port of the DTVS.