fuel return line necessary?

I plan to possibly run new fuel line for my 'cuda. Is the return fuel line and everything else that's on it necessary? It is a '72 that had the canister. Fwiw I have a 450 horsepower 440 in it now and plan to upgrade another 100 horsepower or more in the future.

Mechanical or electric fuel pump? The return on the electric will help keep it cool.

I have eliminated the return on a few trucks that had the 3rd nipple fuel filter, and then capped the return line with no issues.

But they were not high horsepower.

You might be confusing "return line" with the vapor recovery, AKA "carbon canister"

The evap emissions sytem costs no HP, and you have to have SOMETHING there because "that is" the tank vent system. If you cap the third line, there is no vent. No Mopar in these common "muscle years" of the 60s 70s and even ?? 80s?? used a vented cap. The "pressure vacuum" caps were not intended to be a "vent" just pressure relief

So far as FUEL return, that was the 440/ 426 cars that had little can ---looks like a filter-- above the fuel pump. THESE WORK and prevent vapor lock

You can "make" one of these by using a Wix (or equiv) 33040 (5/16) or 33041 (3/8) filter which has a built in 1/4" fitting with a return orifice. That 1/4 fitting must be "up" whether the filter is vert. or horiz.

I recently replaced my original lines on my 74 challenger.

I ordered a suction and return for a 70 hemi which got me a 3/8 suction and a 1/4" return line.

Then ordered the vent line for a 74.

Installed all 3 and I have been using both factory vapor separators front and back. I use the factory VS bolted to the mechanical fuel pump up front and made sure there is a .060" restriction in my return line. I have run like this since 2005 with my old 5/16" lines and rigged a rubber line for a return. I have run the car hard in hi altitudes in 100 degree heat at 120 mph for over 5 miles at a time and never ran out of gas. My car always starts even in 115 degree heat in Vegas, Reno and at the Bonneville salt flats. I ran the car for miles at a time at Bonneville on a 95 degree day at near wide open throttle. Talk about a serious test of the fuel delivery and cooling systems.

So with todays gas and if your going to replace lines than I surely would put in the return line.

Pictures of my 74.




There's my suction and return, I covered them in heat sheild.

I dead headmine, not an issue. I might run a return when I install the NO2 system.

i have a 650 horse street car with elect pump,no return no problems.