Choke tube thread size?

iceblade10

I am in the process on converting my Hornet from a single carb setup, to Twin H.  I bought 2 "universal" choke tube kits from Dorman for the 2 Carter WA-1 2113S carbs.  However, the compression nuts do NOT fit on the threaded nub by the choke.  The threads are different.  I can barely get 1 thread on before it starts to bugger up the nub.  Even the nut from my Carter 2-bbl single carb does not fit.  Is this some kind of proprietory thread size?!  Does anyone know what nut I need, and where I can get them?!  There are a ton of Twin-H Hornets out there... what nuts did you guys use??