# Fuel Pump Return



## GTOKID64 (Jan 20, 2009)

Hi Guys - I have a new fuel pump with a return nipple. This is a 1974 400 with tri-power that I'm putting in a 64 GTO. I have read here that I can block off the return. Will this effect the fuel pressure at all? I was going to test it first, but I wanted to check with you guys first. Thanks.


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## BearGFR (Aug 25, 2008)

If your car doesn't have a return line, shouldn't hurt it at all. Just cap the fitting on the pump. If it gets hot where you live, having a return line would help guard against vapor lock problems though.

Bear


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## lars (Sep 28, 2004)

:agree
Modern fuels have higher vapor pressure than the fuels in 1964, making our cars much more prone to vapor lock and fuel starvation. This is more of a problem in hot weather, but can be noticable under any conditions. Rather than cap off the return port on the pump, you'd be much better off running a return line back to the tank and using a return system - it will make your car much more reliable in warm weather and with the current available pump gas.

All the engine installs I'm doing now have one of two types of return systems on them so that I don't get customer complaints on fuel starvation. If a return-style pump is not used (if you have an aftermarket high volume pump with no return), the simple and cheap way to do it is with a fixed-oriface bleed system. Here is one installed on a QuickFuel equipped 455. It bleeds and returns fuel from the rear carb inlet - as close to the carb as possible to keep the fuel circulating. You can do the same on a Tripower system by running a "T" off the fuel inlet line system near the rear carb:










For systems running higher pressure pumps, I run a return-style regulator at the carb to keep a good volume of fuel flowing through the lines at all times. This one is on a 407 Chevy with a Demon carb, but could just as easily be used on a Tripower system. This works really well:










However you decide to do it, I'd suggest, at a minimum, so run fuel return back from the stock pump that you have - it doesn't take much to run a line down the frame rail and pop a fitting into the top of the tank sidewall for the return. 

Lars


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## geeteeohguy (Feb 2, 2008)

You can also run a fuel vapor/return system with a '66-'67 style three-connector fuel filter. I have one on my '67 (the car came with it new) and it consists of a canister filter that mounts up by the T-stat that has a 1/4" outlet on the upper side next to the main fuel outlet, which is plumbed back to the return line in the frame of the vehicle. This was a '66 and '67 Heavy Duty cooling system accessory, and preceded the vapor return fuel pumps. Since I re-installed my vapor return system, the car runs better in hot weather, and has not vapor locked. (used to be an issue). The components for this early system are available from the vendors.


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