I took a chance on a 1 1/2" model E Ensign snail shell carb.  The Best model S Thirty uses the model G snail shell Ensign.  What was the model E used on, because it shows up in the Accessory and Supply Catalog Form 1736 from May 1944? A picture of the page from the Accessory and Supply Catalog and then some of a G and an E next to each other.  The E has the correct ball joint on it and has marks on the intake horn where the pre-heater could have been tightened down.  That picture is not the greatest.       
Thanks
Ken