What to put on these threads?

YY1 said
Isn't that fuel pump inlet a flare joint?

It does look like a flare joint to me inside, but the Holley docs say it's 1/4 NPT. Perhaps both?? Anyway, I'm connecting 5/16 fuel hose to it. The outlet is the same as the inlet, I'm expecting to go with a flare end hard line there.