I’m assuming you’re referring to the EFI Fox Stang. In which case, yes, they do have a return line. Not sure how much line you will need, but just make sure the fuel line you are using is made for fuel injection. EFI fuel lines are made from nylon, rather than the rubber lines you’ll find in a carbed car. Carbs run at about 5-10 psi, where EFI has about 40-60 psi. If you run that much pressure through a rubber line, all you’ll get is a huge mess as soon as you start the engine, and most likely a huge fire. The 92 and up 4cyl cars have crank sensors for the DIS ignition, the 5.0s do not.