The barb fitting on the fuel pump should thread out, and you put in a 6AN to 3/8" (?) fitting.
Something like the following (confirm your pump fitting size for yourself):
https://www.amazon.com/Russell-66046...82452829&psc=1
If for whatever reason it doesn't thread out, then can hose clamp the other end of the line, as the ID should be about the same, or go from a 6AN to a barbed fitting, then have a run of line between the two barb fittings.