I have made inserts to fix the threads. I used to take 9/16” NF bolts and drill and tap them for the inlet threads. I would cut them off the bolt so I had a short threaded insert. I tapped the inlet 9/16 but not all the way thru. That way the insert can not screw thru. I never had a problem or a leak. The inlet gasket is big enough to cover the insert and you would never strip the steel threads.
Andy's way of repairing the fuel inlet seems to be a good way to do it. Be sure that the gasket surface is perpendicular to the fuel inlet threads. Matt, from Iron Trap Garage also has a good way to repair the fuel inlet.