Ivan, I think most Khamsins came from the factory with the smog-pump, but the Euro-cars had speghetti headers and no thermal reactors. I have yet to see the arrangement and what the bracket looks like on a not so equipped Khamsin. I suppose it was Maserati's way of showing the authorities they were doing their part to keep the environment clean. Euro cars have the 2 vac valves, but I think the capsule on the distributor is an advance rather than a retard mechanism. I have not tested this, but assume that one of the vac switches is governed by the micro-switch on the rearmost carb to cut vacuum to the capsule on the distributor at idle. The switch would simultaneously engage the clutch of the smog-pump so the gasses out of the exhaust smell like roses and the pump doesn't drag idle speed down? Best, Jack.