I don't know for sure, but it sounds like they don't have all the information needed for your model. Have you considered aftermarket alternatives?
Holley makes a 670 cfmTruck Avenger model that is supposed to be really good for wheeling for $390
Edelbrock makes a 600 cfm Performer model that goes for $230. You can even buy a remanufactured one from Jegs for $184.
Personally, I'm happy with my Edelbrock. It never let me down and it's easy and cheap to rebuild ($35 and 2 hours).
1982 CJ8 - AMC 304 (Howell FI), TF-999, Dana 300, SOA, Stock Dana 30 & AMC 20, 31" MTs.