3x2 setup having problems

[boug58]

I have a 3-duce setup on my 348 1958 impala. I bought it from vintage speed,
I have put two different regulators in line. both holley 0 to 4 1/2 psi, and two different gauges for fuel pressure reading. The problem i,am having is when i start the car up for the first time in the day,the fuel pressure reading i have is set at around 3psi, as soon as i hit the throttle and open the back and front carbs. the pressure gauge will read 0 psi when i come back to idle,and it will stay that way till the next day when i start it up again and it will read 3psi.when the gauge reads 0 psi the car still runs great, why is the gauge going down to 0.

Another question is were should i be getting vacuum from on the center carb, at the throttle plate area , our use the port that is on the front right side just under the bowl area.

[1958 delivery]

Don't know about your gauge reading but you should have the reg set higher, in my opinion. About 5 1/2 to 6psi.
The vacuum at the base is full time, the one at the carb body should be part time, off at idle. I would use the full time source.

[tripowerguy]

The original 3X2 setup has a hollow stud on the drivers side rear carb. This is where you are supposed to hook your distributor vacuum up to. Anything above 6 lbs. will cause the needle and seat to leak fuel by and cause a rich or flooded condition. I run mine at 4 lbs and it never starves for fuel. Am I reading your post right that you are running 2 reg.? If that is the case why? Your vacuum needs to be manifold vacuum not vacuum above the throttle plates. Anyway I have no idea why the fuel pressure gauge would only read when you startup and drop to 0 when you floor it. I would think you have something in the line that is acting like a one way valve. Can you post a picture?:dunno Roy

[boug58]

tripowerguy I should have said that I thought the first regulator was no good so i bought a new holley 0-4 1/2 psi. But it turns out that the first one was good. I,am only running one regulator. Sorry about that one. I just received from ups a New MSD Dist part number 8393 from Summit. I removed my vacuum line and i,am running without it. Initial timing i have at 15 degrees and the total at 4000 rpm is 37 degrees. this dist helped me with the bog i had. I thought it was in the carbs.
In the Dist From MSD they set it up with 2-Heavy silver springs that is the slowest advance, and with a blue advance stop. I,am going to change only the springs at this time to lighter ones. going to put in one light blue and one light silver.
I should have said that at the timing that i,am running know the car starts the best it ever has,and it dosen,t run on when i turn off the key.
The guy that is helping me with all this says that I should go up one or two jet sizes in the middle carb. i still have a little bog, but know it is the gas not the timing. Thanks alot for the help and If you have anything to had me reply.
again thanks alot Boug58

[tripowerguy]

Idealy all the advance would be in at 2500 to 2700 rpm. If you run vacuum advance it will make your mileage a lot better and the engine will smooth out at part throttle. I am really puzzled why the fuel pressure gauge drops to 0 and stays there. That would mean that you are deliverying no fuel but the engine is still running, right. If that is the case then the gauge is lying or you have struck the mother lode by having a car run on air only. Is the gauge in line before the carb's or after the carbs at the end of the line? Are you running a mechanical pump or an electric? As far as jets go if you are running cast iron manifolds then you would probably be OK with 59's straight through, if you have headers and a big cam then 61's straight through would be about right. If you have access to a fuel to air ratio meter then you can set it up so you can drive and watch what happens at idle, part throttle and wide open. Have you drilled out your shooters that the accelerator pump shoots the gas into the venturii? They need to be about .31 and you have to drill them from the back side. You need a nice stream of gas coming out of each shooter that the accelerator pump feeds. This has to be on all three carbs. If you have a weak stream then you bog, kind of like an old man with prostate problems, me. My carbs do a lot better than I do at making a good stream. Roy