So I recently found out the 99 has a returnless fuel system for some reason and obviously the foxbody 5.0s are return type. Has anybody swapped an nb and care to share what they had to do to convert it? It SEEMS like you would just have to run another (return) line to the gas tank but could someone elaborate?

 

Yes. Tap the return into the filler neck.

 

LOL tbone you never let me down! Such great wisdom in so few words I love it!

 

Hi, my solution is to remove the pump and upgrade it to a higher flowing unit, remove the Miata in tank regulator which is on the return line on the pump itself. Simply cut it off and run a hose in its place to the same length. Refit pump assembly, Then plumb the mustang return line into the original Miata return fitting. It is neater this way. Just make sure that you use the Russell hose fittings for the pump end. They can be purchased from flyin Miata.

Cheers