Hemi carb cfm rating

Fuel and Air Systems

  1. dan juhasz

    dan juhasz FBBO Gold Member FBBO Gold Member

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    What was the factory cfm rating for the afb’s on street hemis, 66 and up.
    Also if I wanted to shelve my original carbs can I just buy 2 new edelbrock carbs? Is the air horn the same diameter for the chrome dome air cleaner base?
    Carter used to make the competition series carbs, are they still around?
     
  2. snakeoil24

    snakeoil24 FBBO Gold Member FBBO Gold Member

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    skip them entirely install a single 4 holly and make more power 1050 carters were 550 believe it or not
     
  3. Fran Blacker

    Fran Blacker FBBO Gold Member FBBO Gold Member

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    Think carbs were 585 cfm. Edelbrock air horns are larger. They bases on ebay. Member bought one awhile ago said it was poor quality, have things changed? Might need to machine primary holes on intake. Mancini sells a complete setup, no air cleaner.
     
  4. dan juhasz

    dan juhasz FBBO Gold Member FBBO Gold Member

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    I was really thinking about that also. I still have 426 single four barrel manifold ( from crate engine) if I went that directional what Holley would you suggest for an essentially stock Hemi, 727 auto, 3:23 gear set. Vacuum secondary , double pumper what cfm??
     
  5. Runcharger

    Runcharger Well-Known Member

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    I tried to make aftermarket AFBs work on a stock manifold and they sort of were okay when I changed the jetting to mimic the stock jetting. However for some reason when I got a set of original carbs they were vastly more driveable than the aftermarket ones. I would work with the originals if it were me. I went down this road twice with the same results.
     
  6. F4R/T

    F4R/T Well-Known Member

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    Don’t forget Holley and Carter rates their flow ratings differently . One was wet and the other I can’t recall. But I would skip the fuel leakers and rebuild the carters and be done with them Imo. Carters are very easy to tune and get more out of and don’t have the issues of a Holley. Keep in mind you opened Pandora’s box of opinion!
     
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    • dan juhasz

      dan juhasz FBBO Gold Member FBBO Gold Member

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      That’s ok I like and appreciate all the different opinions and past experiences from members. It’s a great way to avoid things that have been tried but with lack luster results.
       
    • dan juhasz

      dan juhasz FBBO Gold Member FBBO Gold Member

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      I appreciate the input, I’d hate to buy 2 new edelbrocks and hate the results
       
    • dan juhasz

      dan juhasz FBBO Gold Member FBBO Gold Member

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      Do you know if that Mancini setup works with the factory dual quad base?
       
    • dan juhasz

      dan juhasz FBBO Gold Member FBBO Gold Member

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      I also see that Harms Automotive sells specially prepared dual quad setups for street hemis for 1200 bucks for the pair. I would think they did their homework on calibrations for the engine. New edelbrock bases with old afb’s air horns.
       
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      • Jerry Hall

        Jerry Hall FBBO Gold Member FBBO Gold Member

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        • snakeoil24

          snakeoil24 FBBO Gold Member FBBO Gold Member

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          make lufe easy use a 780 vac and notch the divider in the duel plane lots of signal quick start great manners if you get a little crazy then 950 holly
           
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          • Jerry Hall

            Jerry Hall FBBO Gold Member FBBO Gold Member

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            The stock 426 street Hemi had 2 625 cfm Carter AFB's. 1250 cfm total.
             
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            • PLMHEMI

              PLMHEMI FBBO Gold Member FBBO Gold Member

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              '67 Hemi AFB Cheater carbs 750 cfm, they work just fine for me...Scott Smith did mine.
               
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              • Fran Blacker

                Fran Blacker FBBO Gold Member FBBO Gold Member

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                Only knew it was an alternative to stock carbs.
                 
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                • Dave6T4

                  Dave6T4 Well-Known Member

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                  If you look at the factory AFB carbs meant for 2 X 4 applications, they have a weighted air valve in the secondaries. It performs same function as air valve on AVS or Thermoquad. It allows engine to receive only the air/fuel mix it requires for given load/engine speed. It gives smoother transition from part to full throttle. I don't know whether Edelbrocks have this secondary valve.
                   
                • F4R/T

                  F4R/T Well-Known Member

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                  Edelbrock still uses the weighted air valve just like the old afb. Those weighted valves can be Swiss cheesed to speed the opening but you must take the time to fully tune it ie jets , metering rods and springs. I bought several kits and a tuning / rebuild book that helped me understand the tuning side. I really find the old carters very reliable and more precise .. Make an educated decision is your best decision! Scott smith restores my 70AVS and it’s sweet! There is a vendor on here that does them as well and is well respected I just can’t recall who, so you have great options! Good Luck!
                   
                • FitzyB5

                  FitzyB5 Well-Known Member

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                  Harms did mine and they are great. Also work with stock air cleaner. 613313E1-8B7E-4B8C-A99C-B7177545D938.jpeg D61A6331-33A0-49A0-A2C8-041843D275B4.jpeg
                   
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                  • F4R/T

                    F4R/T Well-Known Member

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                    Very pretty!!!
                     
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                    • snakeoil24

                      snakeoil24 FBBO Gold Member FBBO Gold Member

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                      Very nice and Scott Harms is smart for pricing these fair.
                       
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