I photographed these Dodge WC9 (G505) Ambulance examples at Tillamook, Dubois and and New Orleans.
The WC9 is similar to the WC18 and WC27, but the numbers on this example at Tillamook put it in the WC9 production.
The Dodge WC9 Ambulance is a 1/2-ton vehicle, while the visually similar Dodge WC54 Ambulance is a 3/4-ton vehicle. Look for the vertical louvres on the WC9, while the beefier WC54 has horizontal slots.