Yep, That's a 450 series 3 ton , with 161in. wheelbase. Being a '51 model, should have a 270ci. six banger. There should be a "GMC Parts Identification" tag, on the back of the glove box lid, with all the trucks specifications.
Spanky Hardy Collector Of Fine Old G.M. COE Trucks & Antique Holmes Wreckers
