Curious as to the possible application difference between the 3024924, 3029763, 6462137, etc and later sups, 208 and 220 degree ported vacuum switches for the 71-72 350/455 motors? The last time I had to change one out was 1986 on my '72 Gs350, but I am finally getting around to restoring my 71 drop top and I know that it was removed at some point, and I want my ram air functioning as it should, and as I have 3 NOS PVS' laying around I figured I would ask. I did some reading and it seems what ever GM is offering today it seems to be a 208-220 blanket application. thank, J
That thermo-vacuum switch has nothing to do with the air cleaner. It is for the Transmission Controlled Spark Emissions system. The engine will run better without it.
Understood fully, but the bottom port of the PVS has a T in it between carb and PVS, and that is where the Ram Air Motors are connected, on cold start from what I remember the last time I went through this during the 80s, was on cold start the motors are sucked shut to warm the carb, they then open once the PVS gets to temperature. If connected properly, you dont hear the ram air sucking air until the PVS opens. I know this makes the engine run hotter. So if I want to leave it as is without PVS but hook the ram air motors back up again, the air cleaner goes to the passenger side of the carb ?
The air cleaner hose should go to a manifold vacuum connection. ANY manifold vacuum source. That is all it needs. The hose goes to a temperature sensor in the base of the air cleaner. That sensor modulates the vacuum signal to the doors in the snorkels. It positions them to keep the air inside the air cleaner at ~ 115*. That is to help in winter driving and engine warm up.
