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I installed edel 1406 (with 6AN fitting/hose) on sbc 350, with one inlet/one outlet mechanical fuel pump.
How should I install return fuel line? T-fitting before carb inlet with smaller diameter of return line? Or better to replace my fuel pump with new with return line? I saw good edelbrock pump, with nice AN fittings etc (yes, I hate hose barbes)))
Why are you wanting a return line with this carb? All you need is a fuel pressure regulator set to 5.5psig and you're good to go. I'd probably spring for a permanently installed small pressure gauge, too, downstream of the regulator, just to be sure of my pressure at all throttle conditions.
may I ask you show my, what fuel pressure regulator should I get? really, I dont know how construction with pressure regulator works in case of mechanical fuel pump.
with Tee-fitting I may use 6AN fittings for in and out to carb and reducer to 4AN for return line - i was my scenario.
Your Edelbrock 1406, and any other modern 4-bbl carburetor, will operate best with fuel pressure of 4 3/4 to 5 psi at the bowl inlet. Pressures over that can overpower the needle and seat in the bowl and allow the pump to blow raw fuel into the intake manifold, creating a tuning nightmare for you. This is not fuel injection, where more pressure can make more hp, it is carburetion, a whole different animal.
What I like to do, on all new or different installations, is to tee off at the carb and run a mechanical line back to the firewall, then up past the hood lip, onto the cowl in front of the windshield. I like to temporarily mount a mechanical, 0-15 psi, liquid-filled gauge so I can read it through the windshield as I drive down the road. It only needs to be there temporarily until you get the pressure dialed in, so usually using duct tape and tie wraps will suffice.
To run a return line off a mechanical pump, you will need a pump with 3 openings. One is suction from the tank, one is pressure to the carb and the third is a return line to the tank. I highly recommend using only generic pumps from Carter or Airtex.
In my experience, a pressure regulator will not work well with a mechanical fuel pump due to the pulses generated by the pump. Regulators work well with an electric pump, because the pressure generated is rather steady. So, it's best to choose a mechanical pump that has limited pressure in the first place and use it without a regulator. By the time this return port pump pushes the fuel uphill to the carb, it will likely be in the 5 psi range.....
http://www.summitracing.com/parts/cr...make/chevrolet
If you don't want to fiddle with a return line, use a standard 2-port pump....
http://www.summitracing.com/parts/cr...make/chevrolet
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