2 line vs 3 line fuel pump

[rauto13]

I have moved the fuel tank under the bed on my 72 Chevy, the truck originally had the three line fuel pump. When I first moved the tank, I used a plastic tank that had provisions for the vent and also for a return line. I switched to an aluminum tank from Classic Performance and now I have a just one provision for either a return line or vent. I have chosen to use this for the vent, and I am not going to use the return line.

The truck still has the fuel pump with the third line, which has been capped. I have a two line fuel pump ready to install. The question is: Should I run a tee and use the top hole in the tank for the vent and return line or, just install the two line fuel pump and forget about the return line.

Ever since I first installed the plastic tank, the truck has run somewhat rich. I have an Edelbrock carb on an Edelbrock intake. I have switched to the smallest metering rods available and also turned the enrichment screws in to lean the mixture (about one full turn). The truck would always start right up if it ways started every day, but if it sat for three or four days, I would have to crank and crank, like the truck was out of gas, to get it to start. After it had been started that day, it ran good (a little rich) and was easy to start the rest of the time.

I also run through spark plugs about every six months, with very little driving, mostly in town.

Any suggestions would be greatly appreciated.
Sorry for the long post.

[cableguy0]

the problem is the edelbrock carb. likely its too much fuel pressure making it run rich. you want to be right around 5 psi with an edelbrock carb otherwise they wont even adjust out. even with the stock pump you will probably need to run a regulator

[rauto13]

Thanks for the reply, but I am wondering should I keep the three line pump and run the return line into the same fitting as the vent fitting, it would have to have a tee at the fuel tank, or should I just switch to a two line pump?

I will get a fuel pressure regulator, do they make one with a place to hook a fuel pressure guage?

Pics would be greatly appreciated.

[cableguy0]

you can just use a three port regulator one inlet two outlets. your only going to be using one outlet for the edelbrock. then screw in a reducer fitting to run a gauge.i would t into the vent if the it could end up blowing the fuel out the vent tube from the return line. if you use a vented gas cap and just use the other fitting as a return you should be fine

[rauto13]

The reason I am wanting to vent the tank is so that I can fill the tank without fuel trying to spray back out the fill neck. I have a fill neck from a 90 Chevy pickup that has a place for a 5/8 vent line to hook up.

I also hate just barely holding the gas nozzle open so that I can fill the tank, this is the only way I can fill it right now. Any amount of volume of fuel flowing into the tank backs up in the truck's filler neck and stops the gas station pump, or blows gas back out the fuel fill on my truck.

[cableguy0]

you could always drill another hole in the tank and add a return. its only plastic. just screw in a fitting and seal it up good.

[djracer]

you shouldn't need a return line unless you were running fuel injection! Just change the pump and try it before you even get a regulator!