Trying to make a basic air hose w/gauge to plug into the fuel feed lines at the secondary filter to apply air pressure to each feed line, then see which bank bleeds air (no one seems to sell one). Trying to diagnose on which bank an injector body is leaking.

What size is the male fitting that the fuel feed line screws onto?

Much appreciated

 

All set, someone on Powerstroke got me the fitting size: