I have a copy of the SNL-G-508 that Portrayal Press sells that I do not use any more. The manual is in good condition except for the bendix hydrovac section is a little dirty ( I used the manual as a rebuild guide and the pages got dirty (the oil wept through about 6 pages total) still completely legible.
I will provide a full money back guarantee if you get the books (there are two, a part one and a part two) and do not like them. Just pay to ship them back and I'll refund your $40 (shipping non-refundable).
Portrayal charges $96 for this set.
I will also take CCKW parts in trade and issues of Army Motors. Postal Money order or Paypal ( add on +5% to cover fees).