74 Passenger Car Parts Manual ??

Hello all,

I got one of the 1974 Passenger Car parts Catalog(on CD) to help with my 1974 Plymouth Duster. For the most part it is pretty straight forward with the exception of the part number listing. When you look at the parts list by Group Code (i.e., 2-08-5) you see a breakdown for Drum or Disc brakes and so on. I'm trying to determine what the code is listed under each vehicle code (i.e., V(Valiant) has a "1") sometimes its a 1, 2, 4, etc., is this the QTY required or something to do with interchangeability or something else?

v/r
Ron