According to this website,
http://clubs.hemmings.com/clubsites/chevytalk/gmhistory/1931to1938.html,
some of the COE trucks produced in 1937 had a Canadian Pontiac 224cu in motor, which was an enlarged version of the Chevrolet 216cu in engine.
Could the "BFC748675" engine serial number fit in with the Canadian Pontiac 224 engine numbers?