Zenith vs tillotson threads

[Tom maxwell]

GuysAre the threads where the gas line screws into the zenith and tillotson the same. 9/16 hex 1/2 ..20 threads. ?
I see that in Brattons page 59. 2013 edition
Thanks
Tom

 

[Tom maxwell]

I'm having a slight problem going from a tillotson to a zenith screwing in the same gas line

 

[SteveB31]

Both Carbs, use the same gas line.