Jim Carter, Chevs of the 40s, and Classic Parts catalogs are one way to quickly see what is interchangeable. They are listed in the Links section of Stovebolt.com

This 1946 Chevrolet Truck Specification Manual has a lot of information about chassis, rear-ends, braking systems, etc.

A Truck Shop Manual is on-line and, if you plan to keep your truck for a while, you should consider buying one. Differences in parts between different sizes of trucks are often made evident in this manual.