When I took my old fuel rail/injectors out, I just looped a piece of fuel line from the send to return hard lines on the passenger side to avoid any fuel leakage. Now it's been long enough (and I didn't label them) so not sure which is which. I couldn't find a pic in my haynes. Granted I could jumper the fuel pump to ground and see which one has gas shooting out of it, but I'd rather not. :gay:

On a up note, 550cc injectors and dual feed fuel rail are in and everything is pretty much wired up!

 

on my 91 the hardline closest to the front bumper is the return, the hardline closest to the firewall is from the pump

 

+1 front is return

 

I always turn the key and watch for a geyser... couldn't tell you which it is by position.