[hanx55]

Currently my '55 has dual 4 barrel Edelbrocks.

I have some issues with flooding(at least that is what i was told here), have to put the pedal to the floor after it has been run for more than 10 mins and you turn off the motor. I am no carburetor guru and do know that running dual cars requires a lot of attention to ensure the linkage is properly maintained as well as ensuring you aren't running to lean/rich, etc.

My question is, should I be looking to replace the 2x4s with just one carb? Since I am an admitted noob and will have enough of a challenge tuning one carb much less two. If I did make the switch how much of a hit would I take in HP do you think(it is pretty fast, at least to me, can do close to a 12 quarter)? Also how much of an improvement in gas mileage do you think I would achieve(currently get around 8mpg)?

And if you were to recommend switching to one carb what is best? Do you think I could sell the 2x4 setup for enough to get a single setup?

Thanks all,

Hank

 

[Ratpackin]

I'm no expert either, but I did run a dual quad on my previous engine for maybe 5 years and never had a tuning problem. I was running a pair of Carter 500s - IE: Early Edelbrocks. My new engine will have dual quads as well.
You can have similar problems with a single. Once you have the current issue sorted, you should be fine. The dual quad can be low maintenance once it's set up. - And looks much cooler.
:anim_25:

 

[r66ss]

Currently my '55 has dual 4 barrel Edelbrocks.

I have some issues with flooding(at least that is what i was told here), have to put the pedal to the floor after it has been run for more than 10 mins and you turn off the motor. I am no carburetor guru and do know that running dual cars requires a lot of attention to ensure the linkage is properly maintained as well as ensuring you aren't running to lean/rich, etc.

My question is, should I be looking to replace the 2x4s with just one carb? Since I am an admitted noob and will have enough of a challenge tuning one carb much less two. If I did make the switch how much of a hit would I take in HP do you think(it is pretty fast, at least to me, can do close to a 12 quarter)? Also how much of an improvement in gas mileage do you think I would achieve(currently get around 8mpg)?

And if you were to recommend switching to one carb what is best? Do you think I could sell the 2x4 setup for enough to get a single setup?

Thanks all,

Hank

Hank

Holly guy here
Have u thought about running a pair of 500 cfm holleys? or depends on your motor size/

 

[Rich Rogers]

How big are the carbs, and also what engine are you running? I'm using 2 500 edelbrocks on a tunnelram with no progressive linkage, 4 speed and 4:10 gears with 29 inch tires on the street. If I just drive the car like a normal driver, I have gotten 17 mpg but that's after alot of fine tuning and making very minor adjustments to timing and carbs. You have to remember that with 2 carbs every little adjustment can mean alot of adjustment when you do it to both carbs. If it's running too rich or too lean , Edelbrocks have alot of tuning options with accel. pump linkage or just changing the internal springs to give it a smaller "shot". Let us know exactly what you're running so we can help you more. Good luck:anim_25:

 

[cheifyoda]

im running two holley 450 on my bbc tunnel ram and get aprox 17mpg did have spitting and sputting when i first started running this set up but after accelerator pump tunning it fixed the problem and float adjustments. you might want to check the float level. i had same problem with the holleys and when i shut the engine down the float level being to high dumpped fuel down into the engine while it was off flooding the engine. just check all your adjustments and it will payoff. good luck and keep us informed. we all learn from others problems:anim_25:

 

[petes83usa]

You can have similar problems with a single. Once you have the current issue sorted, you should be fine. The dual quad can be low maintenance once it's set up. - And looks much cooler.
:anim_25:

Great advice & I agree....:tu

 

[1956 Sedan Delivery]

Currently my '55 has dual 4 barrel Edelbrocks.

I have some issues with flooding(at least that is what i was told here), have to put the pedal to the floor after it has been run for more than 10 mins and you turn off the motor. I am no carburetor guru and do know that running dual cars requires a lot of attention to ensure the linkage is properly maintained as well as ensuring you aren't running to lean/rich, etc.

My question is, should I be looking to replace the 2x4s with just one carb? Since I am an admitted noob and will have enough of a challenge tuning one carb much less two. If I did make the switch how much of a hit would I take in HP do you think(it is pretty fast, at least to me, can do close to a 12 quarter)? Also how much of an improvement in gas mileage do you think I would achieve(currently get around 8mpg)?

And if you were to recommend switching to one carb what is best? Do you think I could sell the 2x4 setup for enough to get a single setup?

Thanks all,

Hank

I had two Edelbrock 500`s on 327 and had a few problems at first then got it running pretty good but was allways hard to start.
After a while I got sick of it and went back to a 750 Vac sec Holley and the car went like a dream straight up just like it did before I had the dual quads even though it was a different Holley.
I reckon if you are close to 12`s now you will probably do 12`s if you get rid of the Dual Quads.
I would just run an Edelbrock RPM Performer and a 700 or 750 carb.
the dual quads look great but can be painfull at times.
I know some people love dual quads but that is their choice.

 

[MRWRENCHMAN]

Hank , More then likely you probably have some foreign material in the carbs . If something get between the needle and seat it wont stop fuel flow to the carb.This about the only thing , besides float level that will make a AFB style carb flood. I had a 63 SS409 years ago that every time you tached over 7000 the needle seats wound come loose , make sure they are tite . Don

 

[Hombre0321]

You didn't mention how much Fuel Pressure you have with those two Edelbrocks. Flooding is indicative of maybe too much pressure over powering the needle and set or a carb that is just not set-up right as to float level. probably doesnt have anything to do with the running of "TWO" carbs as one carb can flood just as easy if its not set-up right.

Also running rich can happen to a single carb set-up, the two fours alone are do not have an inherit problem with running rich. They do need to be set-up correctly to perform right but once set-up they should be trouble free. They DO NOT require a lot of attention if done right.

You mention 8MPG well thats not right. You low milage is also telling you something. I am running two fours on both of my chevys one a 55 with a pumped SBC full roller motor, running tons of cam and I get better than that, and I have a lead foot. The 55 is a four speed car and I have a hard time keeping my foot out of it. My other car is a 57 2 door wagon running a 383 and another 4 speed, Edelbrock Vintage manifold and two 600 CFM Edelbrocks set up for two fours and it gets 15 to 17 most of the time, well sometimes maybe more correct ( remember the lead foot thing).

As to switching from the two fours to a single carb and taking a hit on HP. Maybe but probably not, today we have some great carbs much better than back in the day. There are several carbs ( single carbs) that could and will out perform your two four Edelbrock set-up. Wish it wasn't true but it is, in some cases you can go faster with a single carb than with duals. I'm and old school guy and I'm keeping my two four barrel cars, but if I am honest with my self, its really about the looks more than anything else......

Roland

 

[hanx55]

Thanks for all the replies here is the information I have on the motor from the guy I got the car from:

The engine was from a 1976 Suburban. The piston bores were bored .060 over. That makes it about a 360 ci”. The compression ratio is approximately 9-3/4 to1. Every part in the engine has been replaced with expensive hot rod parts. The pistons, rods, steel crank, roller rocker assembly, oil pump distributor, Eldabrock 600 cfm carburetors and starter. The cam is a 292 with a 501 lift. I built the motor myself. The transmission is a 700R4 with a 3000 stall converter. The rear end was built by a guy in Tulsa, it’s an Auburn 411 posi tack.

 

[buffalohad]

I have a 66 327 that ran dual quads on, I had two 600 holleys on an Edelbrock XC-8 crossram. It was to much for a small block try running a couple of 450 it should run much better.

 

[56owner]

the fix

IF YOU EXPECT THIS CAR TO START EASY AND RUN SHARP GET PROGRESSIVE LINKAGE IF THE CARBS ARE IN LINE. TAKE THE FRONT CARB AND LOOK FOR THE TRANSTION SLOT. CLOSE THE THROTTLE BLADES UNTIL YOU CAN SEE ONLY ABOUT HALF OF THE SLOT AND ADJUST THE IDLE SCREWS OUT ABOUT 1 1/4 TURNS TO START. DO THE SAME WITH THE REAR CARB BUT SET THE IDLE SCREWS OUT 1 1/2 TURNS. INSTALL THE CARBS AND ADJUST THE REAR CARB WILL OPEN THE THROTTLE BLADES STRAIGHT UP AND DOWN AND NO FARTHER WITH THE LINKAGE. NOW HAVE SOMEONE GET IN THE VECHICLE AND HOLD THE PEDAL DOWN AND INSTALL FRONT CARB LINKAGE AND SET THROTTLE BLADES UP AND DOWN WITH THE SLIDER LINK.
NOW GET A DIGITAL TAC TO SET THE IDLE .TURN THE SCREWS ON THE REAR CARB ONLY TO HIGHEST RPM POINT THEN RESET YOUR IDLE SPEED TO DESIRED RPM. NOW REST THE FOENT CARB IDLE SCREWS FOR LEAST AMOUNT OF RPM CHANGE DURING IDLE .ONCE YOU ARE COMFORTABLE WITH YOUR BASE TUNE UP CHECK THE TIMING AND CORRECT IF NECESSARY. NOW TRY A STREET CRUISE AND A FEW SHORT WIDE OPEN ROMPS. IF YOU FEEL ANY HESITATION OR BACK FIRE TEY OPENING ALL IDLE SCREWS ABOUT 10 DEGREES OF SLOT TURN AND TRY AGAIN. THIS SHOULD GIVE A SMOOTH RUNNING SETUP

 

[icody]

I ran the 2 Edelbrocks on a 1969 AMC 390 andI worked for me...The Lighter weight spring allowed the fuel metering rods to close better and quicker on lower vacum. Wonder if that could be your issue as well since you have a pretty good Cam!

 

[g55keeney]

I have been running 2 Holley 600 mechanical secondaries for over 10 years with no starting or driving problems.:rock: The dual setup is a little more labor intensive to set up, but TONS more fun when right:happy0065:. The hit on HP would be negligible provided the right single carb is picked:sad0049:. What you need to decide is if you want the COOL:anim_46: look or the same as everybody else look.

 

[TheHotrodHandyman]

IF YOU EXPECT THIS CAR TO START EASY AND RUN SHARP GET PROGRESSIVE LINKAGE IF THE CARBS ARE IN LINE. TAKE THE FRONT CARB AND LOOK FOR THE TRANSITION SLOT. CLOSE THE THROTTLE BLADES UNTIL YOU CAN SEE ONLY ABOUT HALF OF THE SLOT AND ADJUST THE IDLE SCREWS OUT ABOUT 1 1/4 TURNS TO START. DO THE SAME WITH THE REAR CARB BUT SET THE IDLE SCREWS OUT 1 1/2 TURNS. INSTALL THE CARBS AND ADJUST THE REAR CARB WILL OPEN THE THROTTLE BLADES STRAIGHT UP AND DOWN AND NO FARTHER WITH THE LINKAGE. NOW HAVE SOMEONE GET IN THE VEHICLE AND HOLD THE PEDAL DOWN AND INSTALL FRONT CARB LINKAGE AND SET THROTTLE BLADES UP AND DOWN WITH THE SLIDER LINK.
NOW GET A DIGITAL TAC TO SET THE IDLE .TURN THE SCREWS ON THE REAR CARB ONLY TO HIGHEST RPM POINT THEN RESET YOUR IDLE SPEED TO DESIRED RPM. NOW REST THE FRONT CARB IDLE SCREWS FOR LEAST AMOUNT OF RPM CHANGE DURING IDLE .ONCE YOU ARE COMFORTABLE WITH YOUR BASE TUNE UP CHECK THE TIMING AND CORRECT IF NECESSARY. NOW TRY A STREET CRUISE AND A FEW SHORT WIDE OPEN ROMPS. IF YOU FEEL ANY HESITATION OR BACK FIRE TRY OPENING ALL IDLE SCREWS ABOUT 10 DEGREES OF SLOT TURN AND TRY AGAIN. THIS SHOULD GIVE A SMOOTH RUNNING SETUP

This info ^ should get you very close on the initial set up for your dual quads.

I run dual Edelbrock 500's on my 55 wagon and once set up correctly they are trouble free. They have been on the car for about 60,000 miles with no issues at all.

-Bruce

 

[Black 55]

Hank, if you need the carbs set up ccorrectly you might want to talk to Damon Kuhn at diamondback engines. He specializes in those carbuerators and builds them for racecars all over the US. He is in the Houston area or you can call him and he'll tell you what to do. He's a very nice guy.

www.diamondbackengines.com