Russel makes these fittings
part numbers 640860 5/16 & 640850 3/8
dont be like me.. look before you leep. i ran out and bought a wix vette filter/reg. for $50 and had to go right back and return it. with these fittings you can run an inline fuel filter.. i chose to go with a ac delco oem filter for the 2001 5.3 vortec. $25 but with being able to run the inline filter your choices are vast.