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On a side note here, I'm considering adding an Air Filter Service gauge. Usually they are mounted on the engine side of an air filter box, but these older systems are directly on top so that idea can be a little challenging I think, to mount it properly it would be in the direct flow of air into the throttle body which I think will present inaccurate readings. This is not the exact unit I'm considering but most GM ones are about the same.Any ideas here guys? Theories about how and where to mount it? Directly in the air box or remotely and supplied with a vacuum hose?