Or just keep it simple and use -5oring boss to -5 jic fitting on the pump and keep it all -5, that's 5/16, which is the size of your fuel line on the truck ( yes it's 3/8 in a few places, but back at teh tank it goes down to 5/16 so that is the nominal size and it is larger than the ID of the tubing that was on there with the olive setup) and the -5 fitting is redily available from pump shops since it was an optional inlet fitting on some DB2 pumps in different applications ( when I went to the pump shop to ask for a taper fitting to go into our style pump it took the guy a grand total of about three seconds to come up with it, he reached in the drawer and grabbed straight for the thing, so obviously it was a standard interchange.