I would expect that this truck was also equipped with a hydrovac brake booster. If so there would be a large vacuum line running from the manifold below the carb to the firewall and down under the cab to the brake booster. The photo appears that your's has such a vacuum line. You should check the condition of said line as it's important for the brakes. It may also have a vacuum reserve tank mounted on the frame. Some of the two-tons were equipped to pull trailers with vacuum brakes. Truck tractors were all set up this way. On a straight truck, there would be a pintal hitch and glad hands at the rear; and if so it would doubtless have had a two-speed axle.

1951 3800 1-ton
"Earning its keep from the get-go"
In the DITY Gallery
1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.