I have a stock 350 w/edelbrock 1406 on an 85 chevy van. Have run this set up coast to coast twice a year for 10 years. Finally decided to put on a banjo fitting, new gauge, holley pressure regulator. Running at 5 psi. Replaced all fuel lines to my stock fuel pump. Also have an innovate dual A/F guage. Vacuum is fairly steady at 19 inches at idle with A/F around 15. Timing just checked at 9 advanced.
After adding these new parts it now drops A/F to 9.3 on both banks and stalls pushing black exhaust, while trying to accellerate. Can power brake and have it do the same. Adjusted floats in carb to 7/16, checked all vacuum lines & timing.
I'm stumped!

 

What size is the line to gauge from the fitting? Reaching for straws, but if you are running 3/8 " to both carb, and gauge, might be float dropping as it should, and then not recovering from the excess gauge line. With the regulator, and original pump, I am assuming it is mechanical, and you shouldn't need the regulator.

 

I believe the hose or fuel line is 3/8. The gauge is mounted in the banjo fitting, then goes to regulator, filter down to pump. I was told the mechanical pump is putting out up to 9 psi and edelbrock likes 6 or a little less.

 

I originally came straight off the carb then to a gauge on to a different regulator ( a dial type that began falling apart) then filter down to pump. I believe same size lines. Ran that for several years but gauge and regulator started falling apart so I went with edelbrock banjo fitting for a neater install.

 

Did you check the float for any pin hole, leaks?

 

I checked the floats this morning to make sure they were set correctly and both floats had nothing in them. So I don't believe they are leaking.

 

I have just checked all vacuum lines, intake and carburetor with carb cleaner, can't find any leaks. Have new plugs, cap and rotor. Have vacuum at vacuum advance but haven't put a timing light on to check it. Will do tomorrow.

 

You should pull the vacuum off the distributor when setting the advance, one thing, is the choke plate open when running under these circumstances?

 

When I set the timing I remove the vacuum line on the vacuum advance and plug it. The choke is opening as it should as the engine warms and is fully open when all this happens.

 

The quadrajets were notorious for internal plug leaks. I've only had one edlebrock on my son in laws 71 truck. So, I think you have an internal leak in the carb, with that said, I don't know where to tell you to look, I would however visit forums that are about edlebrock, good luck!