Heater Hose Fitting for Champion Radiator

[tuckerd1]

I know I read this somewhere but I can't find it now. Where have yall found the heater hose fitting for the Champion radiator? Is it a 5/8x 18 thread? I sure could use the help.

 

[tuckerd1]

After further checking, I think it is M16 x 1.5 (male) to 3/8" NPT (female) Thread Adapter. Can anyone confirm this? If so you can get them at http://www.threadtoolsupply.com/aluminum-thread-adapter-m16-38npt.html