Rich, I checked out my stash....nothing richer than the AX's (.397 tip).
The DF and DG's are virtually identical (.340). Other .340 tip dia. rods are the DU, DS and CF if that helps your search. Here's the GM number on a couple of the rods:
-DF: 7048512
-DG: 7048890
-CF: 7044775
The EF's @ .567 are good candidates for lathe turning to what you need. You might want to try Dean Oliver @ Deano's Carbs:
http://deanoscarbs.com/