750cmf elder brock carburetor fouling plugs

[Matador red]

What is best carburetor to use on69 Pontiac 400 engine ram air3heads  ram air4cam  headers dual exhaust with elder rock rpm  intake 

[Frosty]

What are you looking for with this combination?

Reliability? Economy? Seat of the pants acceleration? All out performance for drag racing? Street/strip combination? Auto cross? Simple street cruising?

[Matador red]

Not to carbon up new plugs in 100miles something isn’t right 

Have eldelbrock 750 comfy carb on it now bought new 

[Frosty]

Hmmm....if the plugs are fouling, that sounds like you are running way too rich (assuming there is no oil leak or anything else wrong with the motor). A 750 cfm carb should be plenty for the car except perhaps all out drag racing. I think a good carb tuning is what you really need. Do you know a good carb tuning wizard in your area?

What spark plugs are you running? You might want to run a hotter plug to help burn off the carbon too.

You can get add an aftermarket air/fuel ratio gauge. This will require you to drill a hole in your exhaust system near the header collector and install an O2 sensor. That way you know if you are running too rich or too lean at any point in the rpm range.

Edited July 31, 2023 by Frosty

[indymanjoe]

is your exhaust restricted? whats the whole system consist of? does your choke pull off work?

[Last Indian]

Wow that’s a whole can of worms to open up! Frosty’s right, to much fuel and no the carbs not too big. So some questions are in order! How does it run? Sputtering, boggy, good, bad what?  I know edelbrock carbs, but I’m not familiar with a comfy carb by them. Still several things come to mind. If it is an electric choke is it working right? Vacuum secondary’s? Are they connected to the right vacuum source. The base gasket, these often cause lots of problems if it doesn’t complete the right connection between the carb & the manifold. Also some manifolds can’t be used with certain carbs because of their design and the carbs design.

So can you give us more info? I presume the manifold is a performer rpm air gap? Right? But can you give us the actual carb model. 

[64 kiwi boni]

JustA my two cents . Your 750 straight out of the box  is too big for the 400 jetting will be wrong 

you should really be using a 600 to 650 max cfm edelbrock 

unless you have the motor set up for racing 

start at the beginning with the basics like the guys have suggested , but chat with the team at Edelbrock Would be a wise move … or google the formula for how many cfm your motor should have 

Edited August 1, 2023 by 64 kiwi boni

[Matador red]

5 hours ago, Frosty said:

Hmmm....if the plugs are fouling, that sounds like you are running way too rich (assuming there is no oil leak or anything else wrong with the motor). A 750 cfm carb should be plenty for the car except perhaps all out drag racing. I think a good carb tuning is what you really need. Do you know a good carb tuning wizard in your area?

What spark plugs are you running? You might want to run a hotter plug to help burn off the carbon too.

You can get add an aftermarket air/fuel ratio gauge. This will require you to drill a hole in your exhaust system near the header collector and install an O2 sensor. That way you know if you are running too rich or too lean at any point in the rpm range.

 

5 hours ago, Matador red said:

Not to carbon up new plugs in 100miles something isn’t right 

 

4 hours ago, indymanjoe said:

is your exhaust restricted? whats the whole system consist of? does your choke pull off work?

Have eldelbrock 750 comfy carb on it now bought new 

I thought carb was too big will get with eldelbrock never thought of that or get smaller cmf carb thanks I needed a second opinion just confused 

[Matador red]

Exhaust 2 and a have inch plus headers  plugs 4sets in 1800 miles went hotter heat range have e3s in now 

[Last Indian]

11 hours ago, Matador red said:

 

 

Have eldelbrock 750 comfy carb on it now bought new 

I thought carb was too big will get with eldelbrock never thought of that or get smaller cmf carb thanks I needed a second opinion just confused 

Yeah, sorry I have to disagree with Kiwi. That carbs not to big for that motor with the cam you say you have! Especially the primaries! Which is predominantly what you run on, unless you have your foot to the floor all the time! There is something else going on! So I repeat we need more info. You say comfy carb, but there is no Edelbrock carb called comfy carb, so what carb part number is it? I still suspect you have the secondaries connected to the wrong vacuum! We can’t help if you don’t answer the question.

[Last Indian]

To explain a little further, CFM ratings are misleading when not viewed in relationship to the entire system! Manifold, heads, exhaust & the most always forgotten air inlet setup. Your 400 cid engine will flow about 500 to 550 CFM! But restricted inlet or outlet will reduce that number. Yet that restriction translates to a lower output number for the carburetor, because it can’t flow more fuel in a Venturi effect since the air flow isn’t there! Additionally the front two barrels or what are called the primaries only flow about 500 CFM! 
Your carb is not to big! You may need to change jetting, but you’ll only be able to determine that after you do the needed work to determine the problem.

Edited August 1, 2023 by Last Indian

[64 kiwi boni]

6 hours ago, Last Indian said:

Yeah, sorry I have to disagree with Kiwi. That carbs not to big for that motor with the cam you say you have! Especially the primaries! Which is predominantly what you run on, unless you have your foot to the floor all the time! There is something else going on! So I repeat we need more info. You say comfy carb, but there is no Edelbrock carb called comfy carb, so what carb part number is it? I still suspect you have the secondaries connected to the wrong vacuum! We can’t help if you don’t answer the question.

you know i did that intensionally Last indian , i wanted your thoughts on cfm !!🙂

[Matador red]

19 hours ago, 64 kiwi boni said:

JustA my two cents . Your 750 straight out of the box  is too big for the 400 jetting will be wrong 

you should really be using a 600 to 650 max cfm edelbrock 

unless you have the motor set up for racing 

start at the beginning with the basics like the guys have suggested , but chat with the team at Edelbrock Would be a wise move … or google the formula for how many cfm your motor should have 

 

5 hours ago, Last Indian said:

To explain a little further, CFM ratings are misleading when not viewed in relationship to the entire system! Manifold, heads, exhaust & the most always forgotten air inlet setup. Your 400 cid engine will flow about 500 to 550 CFM! But restricted inlet or outlet will reduce that number. Yet that restriction translates to a lower output number for the carburetor, because it can’t flow more fuel in a Venturi effect since the air flow isn’t there! Additionally the front two barrels or what are called the primaries only flow about 500 CFM! 
Your carb is not to big! You may need to change jetting, but you’ll only be able to determine that after you do the needed work to determine the problem.

Ordered rebuild kit carb is a1411 from 2007 been sitting will start there .using timed vacuum for distributor will switch to manifold vacuum also will switch power brake booster to carb brake port from intake port edeldrock technician was very helpful didn’t know I could call them until this site referred the idea to me . Thanks to everyone that helped 

[Last Indian]

11 minutes ago, 64 kiwi boni said:

you know i did that intensionally Last indian , i wanted your thoughts on cfm !!🙂

Chris you are such a character! 
Here’s a little more. To change the stoichiometry of combustion you must change the fuel to air ratio. So with a given volumetric efficiency (air flow) of the engine, minus the carb you must be able to either restrict that flow in some manner or change the way you meter the fuel in. So if you put a 750 CFM carb on a max rpm 500 CFM engine that engine will not flow 750 CFM. But it can run rich with fuel if not properly jetted. So while a 750 CFM carb may seem to big it’s really a jetting issue not CFM.

Case in point! My “69” Z was the famous 302. By all know standards the engine should have had no more than a 500 CFM carb. But out of the factory it came with  780 CFM & if you ordered the Cross Ram manifold setup it came with two 585 CFM carbs. So CFM is not that simple.

I had a friend back in the day that had a “69”, but it wasn’t a Z. He got a 302 from the bone yard & wanted to build it like mine. He didn’t get the carb or the intake it he engine. So when it came time for the induction system he just used his stock two barrel manifold & a 500 CFM two barrel carb! ! It was funny as hell. The car would barley move & he couldn’t get it over 25 mph.

[Matador red]

1 hour ago, 64 kiwi boni said:

you know i did that intensionally Last indian , i wanted your thoughts on cfm !!🙂

1411 eldelbrock carb

20 hours ago, Last Indian said:

Wow that’s a whole can of worms to open up! Frosty’s right, to much fuel and no the carbs not too big. So some questions are in order! How does it run? Sputtering, boggy, good, bad what?  I know edelbrock carbs, but I’m not familiar with a comfy carb by them. Still several things come to mind. If it is an electric choke is it working right? Vacuum secondary’s? Are they connected to the right vacuum source. The base gasket, these often cause lots of problems if it doesn’t complete the right connection between the carb & the manifold. Also some manifolds can’t be used with certain carbs because of their design and the carbs design.

So can you give us more info? I presume the manifold is a performer rpm air gap? Right? But can you give us the actual carb model. 

1411 yes air gap intake 

[64 kiwi boni]

Ah seee ! That’s what I am taking about !!!

thank you gary  👍👍👍

I blame the cpap that’s justA come into my life , feeding wayyyy too much oxygen to my brain ! And in turn it wanting more information 

[indymanjoe]

corky here. remember an engine is really an air pump so cfm,s matter but the whole system has to be balanced properly. 

[Matador red]

I’ve heard that before just not much experience on tuning, but trying to learn I appreciate all the information I can get.

[64 kiwi boni]

4 hours ago, Matador red said:

I’ve heard that before just not much experience on tuning, but trying to learn I appreciate all the information I can get.

Darrell, you have a great carb, it will be easy to tune and there is certainly no rocket science in it at all 

now... has anyone here told you we love pictures ??? show us the set up on your motor 

 these guys have sooooo much knowledge and experanance, they can ceratinly help you with advise.... having said that, it was great to hear you called edelbrock .

kiss !!! keep it simple stupid.... go through the basics first ! dont do what i do and over think shit 

 you have a performer 1411...

https://www.edelbrock.com/performer-series-750-cfm-carburetor-with-electric-choke-in-satin-non-egr-1411.html

did you ask the boys at edlebrock what jetting should be in it for your 400 ? 

[Matador red]

15 minutes ago, 64 kiwi boni said:

Darrell, you have a great carb, it will be easy to tune and there is certainly no rocket science in it at all 

now... has anyone here told you we love pictures ??? show us the set up on your motor 

 these guys have sooooo much knowledge and experanance, they can ceratinly help you with advise.... having said that, it was great to hear you called edelbrock .

kiss !!! keep it simple stupid.... go through the basics first ! dont do what i do and over think shit 

 you have a performer 1411...

https://www.edelbrock.com/performer-series-750-cfm-carburetor-with-electric-choke-in-satin-non-egr-1411.html

did you ask the boys at edlebrock what jetting should be in it for your 400 ? 

No they didn’t mention it but I didn’t ask either still researching that part slow getting up to speed everyone has been great on this site

[Matador red]

On 8/1/2023 at 5:00 PM, Matador red said:

1411 eldelbrock carb

1411 yes air gap intake 

Running smooth but no roar got rebuild kit today 

[Matador red]

On 8/2/2023 at 1:54 AM, 64 kiwi boni said:

Darrell, you have a great carb, it will be easy to tune and there is certainly no rocket science in it at all 

now... has anyone here told you we love pictures ??? show us the set up on your motor 

 these guys have sooooo much knowledge and experanance, they can ceratinly help you with advise.... having said that, it was great to hear you called edelbrock .

kiss !!! keep it simple stupid.... go through the basics first ! dont do what i do and over think shit 

 you have a performer 1411...

https://www.edelbrock.com/performer-series-750-cfm-carburetor-with-electric-choke-in-satin-non-egr-1411.html

did you ask the boys at edlebrock what jetting should be in it for your 400 ? 

Will try 

[64 kiwi boni]

very cool mate