Rereading your post, you have the extra port FORWARD of the adjusting screws on one tranny. That would match the vacuum port location on the Chaffee. Maybe you have a Chaffee transmission? In which case, you won't have a complicated linkage from the carb, just a tubing line to it from the intake manifold.  
 
Malcolm
		 
		
		
		
		
		
		
		
		
	
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