The "40", of 404 = 400 series 2 1/2 ton. The trailing "4", of 404, denotes the wheelbase length. If it has the smaller pickup style bumper it's a '41-'42. If larger channel bumper, a '46-'47. You may also want to join up at, www.oldgmctrucks.com
Spanky Hardy Collector Of Fine Old G.M. COE Trucks & Antique Holmes Wreckers
