swapped a 5.0 into a maverick return line ?

i just swapped a 91 mustang efi 5.0 into my maverick do i need to run a fuel return line and if so how do i do that i have a 71 maverick but iam using 76 gas tank so do i just run return into the tank

 

Yes, the EFI will need a return line.

 

is the efi return line pressurelize or vacum or what

 

Pressure, needs to return away from the fuel pickup also

 

I ran another factory hard line, hooked it to my...intank fuel pump...