The '39-40 one shown is a reprint of a period NAPA Echlin manual...excellent, and also inexpensive, but pretty short and not all that detailed.
My choices would be the 1942 Ford Army staff car manual, available in reprint from Portrayal press http://www.portrayal.com/ ,
and the 1946 Canadian shop manual sold in reprint (with a bunch of Motor's Manual spec pages added) as the 1939-48 Ford and Merc Shop manual, available from all the Ford parts places. Only a few minor specifications and distributor disassembly really differ mechanically between 1940 and these later cars...the Canadian one also covers WWII stuff and so covers the minor distributor differences.
I would suggest you get a copy of the FORD V8 Service Bulletins 1938 - 1940 Complete. Avalible from C & G Ford Parts, number P14. It has all the technical details for rebuilding and maintenance you will ever require.