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#1
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holley 4412 mods
I am planning to modify my holley 4412 for more airflow. What I plan to do is open up the throttle plate bores and install plates from an 850 holley 4bbl. Plus bore the venturi out to the same size as an 850. Anyone tried this? What are the issues with removing and reinstalling the boosters? Any input is appreciated
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#2
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Unless you just want to spend a lot of time over a mill and more time retuning your carb-I wouldn't do it.
I assume you have a 700-750 carb now. I think you will be surprised at how little larger ventura will help you -and could actually hurt performance. I believe the real trick for circle track carbs is the fuel curve, not air flow. And not until you get up into the 600HP range do you really need a larger ventura than the 750. I've done what you are planning to do- and experienced real grief until I broke down and bought a professionally built carb. And I'm not talking about an off- the- shelf racing carb. I'm talking about a carb specifically built for your engine. Good luck but I wouldn't do it again! |
#3
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I strongly agree with Sanborn, i wouldnt do it either, recomend C&S, their 4412 will outflow just about anything, their legal or illegal version, the latter will flow well over 550cfm and still pass "go no go gage" make sure what you rules will allow, and set them free with it. We have been running their setups for some 6 years now, and we swear by it, great after sale support as well...
Avenger |
#4
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4412 mods
The carb we are running now is a 500 cfm holley 2bbl so I was hoping for gains from that. I went to a track with no carb rule so I put on a 700 dp and saw some substantial power gains. The track I regularily race at has a 500 holley 2bbl rule.
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#5
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Plenum
Did you have to change intakes to run the 4 bbl or do you have a 4 bbl intake stepped down to a 2 bbl? The reason I ask is that the plenum size may be robbing you of power if you are using a dual plane 2 bbl intake. That is why I prefer the single plane intake if you are restricted to a 2 bbl intake. A person could offset the disadvantage by using a taller carb adapter that allows more gap between the throttle plates and the intake.
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#6
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I am running a 4bbl intake. It is an LD340 edelbrock with no mods, I am considering cutting the plenum divider and a 2" spacer. I ran this intake at both tracks.
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#7
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When caught we run a cast intake off 5.9l tbi engine, dont remember year, just before Dodge when to the bathtub type intake, like early 90's, with adapter. Seems like best flowing intake for a restricted engine...
When nobody's looking and we get away with it, we run an older holley intake, single plenum,very straight ports,dont remember which one, we grinded away all identification long time ago and casted, with a bonding agent, some old casting numbers to fake the intake. Most tracks we go to, freak out and go into convulsions at the sight of a non Gm product anyway. We have mess around plenty with different junkyard intakes, never been very happy with any of them...but if your rules are strict and someone knows what their looking at, I would use pre-bathtub intake, early magnum motors. Avenger |
#8
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Does anyone have a phone number or web site for C&S?
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#9
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c&s
phone # is 1 636-723-4996 hope this helps !! they do make good carbs !
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#10
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Avenger you daid a C&S carb flows over 550 CFM. Do you know at what inches of H20 that it was flow tested at. I've been told that's how certain guys get big flow numbers was using different inches of water. I had mine done and it's 528 CFM. So if that's the case I need a carb. Do you know if they will take mine & do their work to it or do they only sell new?
Thanks |
#11
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Ours was flowed at 560cfm and it did pass the go no go gage, been inspected some time back, we have run both, 2 barrels and 4 barrels set up from them, not cheap!! Their methanol pump will push 9psi at idle and 19psi at rpms.
We run a fuel rail, ball valve set up, it bypasses fuel pressure to the tank at idle, barely 2psi, and as we gain rpm so does fuel pressure, 9psi at 6500 rpm, 10 psi over 7000rpm, we are also very meticulous, we purge system after every race and fill carburator with gasoline. Methanol eats everything!!! I dont know at what inches of h2o it's was tested, all i can say is we have been very happy with all the pieces we have acquired from them as well as the tech help has been great!!! The only advantage to them building from scratch is that they have a deal with Holley and have all the most perfect pieces to build from....they pick and choose what they want. Im pretty sure they'll build what ever you send them, assuming its rebuildable.. Avenger |
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