I believe it is a rochester with a center bolt. Size of spacer plate I have is approx 2.5 inches and oil breather is 2.25 inches.
I guess that the spacer plate is the insulator between the carburetor and the manifold?
Is there some sort of oil breather on/near your carburetor? (oil bath air cleaner?)
The dimension that will be important for easily finding/fitting a non-original air cleaner would be the outer-diameter of the top of your carburetor.
Does your Zenith air cleaner have a clamp at the bottom/base (with a bevel inside that clamp)? What is the diameter?
What is the diameter of the top of your Carburetor? Is there a lip around/near the top of the carburetor?
If those two diameters are close, you could seal any gap between the two with an rubber oil-ring or a rubber seal.
