I can't think of anything much more ridiculous-looking than an Art Deco truck with 20" wheels! Those big fenders will look totally out of place, with a huge wheel with no sidewalls on the tires! Lowering it with a dropped axle will make it look even more comical!

Jerry
OOPS! I was thinking of a 47 or earlier body style! 20's on the 48 would look pretty ridiculous, too!
Jerry