These were used by fleets and commercial upfitters to specify exact specs for conversions and bid specifications. They are cover-to-cover with highly detailed 3-views of each model from Rancheros to F-, C- , N- and H-series Class 8 cabovers.

(While not indicated in the illustrations, the drawings look close to 1/25 scale, but there's no legend on the page to indicate.)

Assuming that someone could surface the 1963 guide (or any year for the unibody, really) it would be possible to find exact measurements and get to choppin'. It would also simplify the task of other conversions based on the F-Series.