EEA is a code for a 1947 Advance-Design truck. The 1946 trucks sold in 1947 were registered as 1947 trucks but were referred-to by GM as 1946 trucks.
20" 5 lug and 20" 10 lug wheels were used on 4000-6000 series 1947 Advance-Design trucks. What are the widths of the tires (although, incorrect width tires can be mounted on the wheels)?
Here are 1946 codes. Is there a metal tag mounted on the cab between the driver's side door hinges?