Gas pedal stop for too large of a carb?

1964SuperStocker

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Everyone knows a stock 348 (or even a racing 348) can't use all 1000cfm a dual quad 1404 edelbrock set up can provide. Granted I also know that a 600 or 650cfm single would work better. (MY SOLUTION) So why not just put a physical stop on the carbs where they will not open all of the way? I don't have the carbs set up in a progressive manner (they are locked to move the same way at the same time) but even if I did then they would both come on when I stopped the pedal to the floor. My goal is to learn more about tuning the engine for the strip then it is to tune it for the street. I have plenty of knowledge and experience to tune for the progressive application of power from a dead stop to a gradual motion forward from a stop sign. I'm wanting to know more about what people do when they have to much carb and not enough engine. I normally launch at about 2300-2500rpm and I have done enough launches now where I can tell where my camshaft drops off and where/when I have to much gas pedal applied. (All of this will change when the new engine and transmission drops in but I seek to learn more about this subject matter. I have several dirt track friends that run actual gas pedal stops so it got me thinking about my application. I can't be an expert in everything but I can sure soak up information/experience I don't have currently on this matter. (Yes I have in fact considered using two 350cfm two-barrel carbs to experiment with on this little 348 engine too.) I know most people on here think about street or big hp strip use. What if someone is using small 348 and using a dual quad set up? Is there a good way to make it work its best other than remove the dual quad intake?
 
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1964SuperStocker

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I thought of that too but I'm not sure that is the right answer yet. Steve might head this way soon and take a look so I'm determined to tune it as well as I can and them have him check my work. I have a local I may turn to for advice too. There are lots of guys that can tune a single carb but not two of them together. :read
 

Don Jacks

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Supporting Member 3
Your off on your thinking Randy.Your 348 won't draw 1,000 cfm anyway.Your carbs have a weighted flapper on the secondary side that will only open as far as the engine will draw it.Get the jetting right and don't worry about limiting the linkage.
 

1964SuperStocker

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Supporting Member 3
Your off on your thinking Randy.Your 348 won't draw 1,000 cfm anyway.Your carbs have a weighted flapper on the secondary side that will only open as far as the engine will draw it.Get the jetting right and don't worry about limiting the linkage.
See, I know Holley carbs and until I fired this dual quad up I have never run an Edelbrock carbs before. Keeping in mind what they have and do and why is hard. I have been watching "how to tune your edelbrock carb" videos and picked that tip up last night. I knew that my engine would never pull 1000cfm and for some reason I forgot to mention the weighted flapper on the secondary side though I knew it was there. My brain keeps jumping back to Holley mechanical secondary. I actually had a back fire a few days ago on start up and my first thought was there goes the power valve, time to pull it apart. LOL!
 

1964SuperStocker

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Supporting Member 3
Learning more about dual quads each day. I picked up the parts to make this little guy to balance my carbs so they act as one. I've used these on British cars but never on a dual quad. I'd love to walk around and put this little thing on everyone's engines at the track and see who is actually balanced and not. No matter how close you think you have it, it should be measured to ensure both carbs are balanced.
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La Hot Rods

Well Seasoned Member
Supporting Member 15
The balance will help with idle, once the throttle opens there isn't much to the balance anymore.
With the common plenumu in the intake it isn't that important on the balance between carburetors.
I have more idle speed in the rear carburetor than the front. I just use the front to help with the idle but for the most part it is just barely open.
 

1964SuperStocker

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With anything, the more you learn the more you realize the current set up is wrong. LOL! Already making changes. I need to learn as much as I can about these carbs and a dual quad set up because I don't plan on running anything else here on out. There are somethings I like over Holley already but we shall see.
 

1964SuperStocker

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Supporting Member 3
Maybe rig up a way to limit the secondary air valves and leave the throttle blades alone.
It was an idea but probably going to keep working the tune until I feel I can't get much more from her, then get crazy with restricting air flow. :crazy. Just checked and the metering rod is .065"x.052" and step up string is orange. I'm pretty sure the primary and secondary jets are factory too at .086" primary and .095" secondary. I have to run to the hardware store in a little bit and pick up some parts. I don't like the carb links connecting the two carbs that I've had on there since the Tri-State dragway runs.
 
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1964SuperStocker

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aah an old school experienced tuner. You remember Ronnie Russell! I’m doing it with two edelbrocks a 3:36 rear and a cast iron power glide small heads 250-280 cam stock vacuum advance distributor and stock torque converter
Robert
I have two Edelbrocks, 3.70 gear, aluminum powerglide, 333 heads and 250-280 cam with electronic distributor and about 3000 stall converter. What hurts me the most (but looks bad ass! :brow) is the 275/60 15 tires out back. At about 28" tall they bog things down a bit. I've got some 24" tires I'm throwing on there to see how it reacts.
 
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