Hy Mike Nelson, that is a very nice truck you have there, and a rare one, that grill and hood were only used for one year, so guard them with your life! Is that an ex firetruck? The 350 series designation gives us a point of reference to order parts, and to know how it was equipped when it left the factory, it also tells us what was optional from the factory. As to tonnage, I have never figured out how that works, and frankly I don't care, if you have to call it something call it a 3 ton. The 270 is a very good engine and it is a GMC engine, where the 216, 235, and 261 are Chevy engines. The GMC engine design was released for production in 1939, it is a full pressure lubed engine with no shims for clearance adjustment, unlike its Chevrolet cousins. Parts for the GMC engines are no harder to find than parts for any engine of the same vintage, in some cases easier, as these engines were used in military vehicles as well, and they have quite a following. According to the serial number you posted your truck should have a wheelbase of 155", what rear axle does the truck have, a single speed or a two speed? Hope that helps.
