So ive built a 2000 f250 with a first gen 5.9, I'm running an hx35 with the same exhaust flange as the h1c. Is this refered to as a 3 Inch flange? It measures 3 at the mating surface but I want to be sure cause I already bought one for an hx35 and it's 3.75

 

So it's 2.5 v band flange in case anyone wants to build a downpipe