I need to install a fuel return line on my gas tank. I was looking under the hood and on the firewall on the passenger side is a line with a rubber plug on the end of it. I haven`t investigated but it appears to be a vent line that may have gone into a smog canister. If that`s the case, could that be used as a return line ? Thanks, Darrel
There is a check valve on top of the tank which that line goes to. You would have to modify it or eliminate it so fuel could flow back into the tank.
You can indeed use that as a return line...I am doing just that on my '72. I know the '77 line is a little smaller, so it may raise fuel pressure. Mavaholic is right...you will need to drop the tank and take the valve at the top of the tank apart. On my '72 there was no check valve per se...but the hole was very small. I originally didn't do this and everything seemed fine...then one day some dirt or something clogged the hole and my fuel pressure spiked to about 100 PSI I burst the rubber part of the line under the car..and then had lots of black smoke from the exhaust (and about 2 mpg) for a bit before I figured out what happened, dropped the tank and enlarged the hole... Anyway..yeah, it can be done.
Thanks for the replies guys. One of my other options is to cut out a 2" section of my filler tube and install a pre-made return neck from Summit. I'm hoping I don't have to do that, but the fuel regulator requires a return.
what are you building that needs a return line to the gas tank. the holley red is a standard pressure pump preset at 7pounds and needs no regulator or return line as far as i know. which probably isn't too far. i'm confused (easily done, just ask my wife). the mallory 4309 is adjustable from 3-12 pounds but your pump won't put out more than 7 max. do you need less pressure? i'm curious. guess that's how i learn.
Unless you have a special application like a blower, there is no need for a return system unless you have certain problems with keeping fuel pressure constant and can't be solved without.
Special application = 58mm TO4 turbo. However, I may save myself the additional work and go draw-thru with a 600cfm Holley.
