Fuel pressure regulator on dual fours

Anyone running dual fours and using a fuel pressure regulator - the kind with two 3/8" out ports? Are you running two regulators with a regulator log or are you just running the single regulator? If just using a single regulator, what size carbs and do you feel fuel flow is good to both carbs?

 

The set up I like is a a Holley reg with 2 3/8 outlets. Run one outlet to each carb.

In the past I have run one regulater to a fuel log, 3/8 line from the reg a fuel log long enough to reach the inlets for each carb made of 1/2" tubing and 3/8 outlets for the carbs. That is what I run on my '55 door slammer way back when i was a kid and switched from 3x2 to 2x4 induction. I have set a few up that way since.

Both of those setups have worked well for me over the years.

I am curreltly building a 2x4 with 2 carter AFBs (625 CFM each) for my small block and will be running the single Holley regulator.

I will be setting up a pair of 600 holleys on my big olds motor I will probably use the log setup on it, just to give a more antiquated appearance. Well that and my recirculating regulator only has one supply port.

Enough info?

 

on the blown big block in my 55 I have a T fitting going to two of the holley regulators. Each regulator feeds two float bowls. Mine is kind of strange, sideways mounted carbs, so one regulator feeds both primary bowls, the other feeds the secondaries.

 

If it's a street (shows, cruzing stuff) car only, you can get away with just one.
But if you want to get the tuning right for high rpm racing, two regulators and two pressure gauges should be used.

Mike

 

Awesome info, thanks guys. It's just for street/cruise use, no racing. SBC and carbs are 500 CFM's, so one regulator should do. One last question, if you run a line from each of the 3/8" ports to each carb, do you just fit on a pressure gauge on one of them?

 

I like to run a regulater on each line, use the reading that is lowest or correct for max pressure to your carbs.

You will find that the pressure varies slightly from one side to the other as a rule.

 

Here is mine. 500cfm Eld's.1 Moon reg.

 

My rule of thumb for the small blue Holley regulators is 450HP per regulator. One regulator works fine for the lower HP stuff but use two for the higher HP applications.

 

That's why I'm running two of them....the passages in the regulators are kind of small.

 

Lawman -
I can't see the regulator so will ask what is probably a dumb question: are you running from one output port on the regulator to both carbs? Is the regulator port 1/2" or 3/8"?


Here's a setup I just saw at the weekly cruise-in last night. I imagine this looks like Porkbeaner is describing.

 

Yep that it what I am talking about. Works just fine for a healty street engine.

 

After having several flooding problems with my two 500s at 7psi I called the tech line at Edelbrock and they recommended 4.5psi and a regulator made by them. It has two outlet ports but the tech guy said to just plug one and it will work fine, they've tested them hundreds of ways. Here's a pic.

 

I think it is 3/8. The reg is part of the preasure gage.