what carb should i use on the new 496 stroker eng

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  1. JNBowen

    JNBowen Member

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    Ok looking for your thoughts, I am working on my 68 charger just pulled the tired old 440 that was a band aid for the car while the 383 was being built. I am nearing completion and want to put the most carb I can on the old girl with out putting to much. So what I have is a 383 block .60 over 440 source balanced stroker kit. 440 source aluminum heads with the upgraded valve springs and seats. Roller rockers from 440 source again. Pro comp cam .545 lift 110 degree lobe separation. Edlebrock high rise single plain entake. MSD Ready to run distributor. I still have to get plugs and a carb because I just dont think the holley 670 is going ot cut it. The engine builder said I need a medium heat spark plug (not sure what that means) but anyway I need ideas for the right carburetor. Keep in mind the ready to run distributor has a vaccum advance and the hide away head lights also use vaccum to open. I have heard of people using a cable to open those but never actually seen it. The one wrapped up is the 383/496. Please shoot me some ideas I dont want it to be limited by the carb but I dont want to get more than I need.

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  2. Mike Gaines

    Mike Gaines Well-Known Member

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    I would get an 850CFM Demon. I bought one for my 505" (850 Mighty Demon) and just love it. It is easy to set the idle also without disturbing the "slot" setting in the butterflies. Check them out on Summit...or better yet...just call Demon and ask them for a recommendation. I love the carb.
     
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    • Xp29h

      Xp29h FBBO Gold Member FBBO Gold Member

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      There could be a few options for you. My recommendation is spend the bucks and buy new no matter which way you go. This could get costly though until you find the right combo.

      I'm running an 850 Holley on my mildly modded 383. It doesn't pull good in early rpm range but I haven't found top end yet. But, the motor has some issues and currently stoking a 400 with the 440source 512 kit. I will start with the same 850.

      Good luck!
       
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      • Dennis H

        Dennis H FBBO Gold Member FBBO Gold Member

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        I too like the 850 Mighty Demon. NGK plugs work well too.
         
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        • theman440

          theman440 Well-Known Member

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          950 cfm
           
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          • 72 Charger SE

            72 Charger SE Well-Known Member

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            I've got an 850 Speed Demon with electric choke that I might be persuaded to part with if you choose to go that route.
             
          • 65hemi

            65hemi Well-Known Member

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            Holley 950 HP on mine.
             
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            • uwss

              uwss Well-Known Member

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              Dyno will tell you ; so spend the extra bucks bring 3 or 4 carbs and try them out. You will need to adjust your timing also.
               
            • Budnicks

              Budnicks You Can Just Thank Me Latter

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              I personally Like Quickfuel Carbs & components the best for Holley type carbs

              IMO If the heads are going to be ported, you need a little bigger carb,
              then I personally would go with the HP 950 Holley
              any of the Holley style of carb form Quickfuel, AEM, Proform,
              even a Demon {owned by Holley Now}, Holley HP series, Promaxx
              none of them are cheap but well worth the extra $$$

              Id also highly suggest to get a couple books or dvds,
              to learn or "actually" know how to properly size & tune a Holley style carb too

              I'd also suggest getting a few different sizes up & down
              of accelerator pump discharge nozzles
              assorted colors acc. pump cams
              assorted sizes of main jets
              assorted power-valves
              {usually need about 1/2 the # of inches of vacuum, the engine makes at idle}
              Assorted gaskets for metering blocks, fuel bowls & secondary plates if vacuum

              I would also add that if you get a regular Holley 4bbl,
              to get better metering blocks, adj. emulsion tubes
              & air bleeds will help to fine tune your specific engines needs...
              If it's a vacuum sec. carbs style carb {great for a street driven automatic}
              I'd suggest to get a kit/set of assorted diaphragm springs,
              so to be able to change rate of opening...
              I'd also suggest if it's a vacuum sec. carb, getting adj. secondary plates,
              to use reg. Holley jets, from someone like Quickfuel or Promaxx etc.

              IMO If your not having the heads ported the HP 850cfm Holley will probably be fine,
              depend really what it is you want, what the end use will be, what are your expectations,
              any Holley style aftermarket supplier, would be a great choice, even then,
              it should still be fine tuned after installation, for your specific combo...
              Don't expect to have it be perfect out of the box, regardless who you get it from...

              CI x RPM dived by 3456 = CFM
              Example;
              496ci X 6000rpm/3456 = 861cfm
              496ci X 7000rpm/3456 = 1004cfm
              that formula is for about an 80% efficient set up,
              which is pretty good for non ported heads,
              for a race motor or spinning higher RPMs &
              getting the most flow capable out of it & ported heads a little more carb is probably better...

              It depend really how it's going to be used ?
              what rpm's you run ?
              what type of trans &/or converter ?
              what camshaft ?
              what altitudes ?
              what gears ?
              what head work & cfm flow rate ?
              what weight of car ?
              there's allot of other factors to consider
               

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              Last edited: Jun 6, 2015
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              • JNBowen

                JNBowen Member

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                Thanks you for taking the time to add so much info I will definately take all this into account. I am leaning towards the 850 cfm. Holley or quick fuel. That formula is awesome. Again thanks for the detailed response. I never realized people were so helpful on these forums.
                 
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                • Car Nut

                  Car Nut Well-Known Member

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                  I have a Holley 750 DP on my stock 383, so a Holley 850 DP would be perfect on yours.

                  Have you thought about a six pack set up for your 383?
                   
                • JNBowen

                  JNBowen Member

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                  NO i have not considered it just do to the complex nature and the added expense. Only because I am not going for a stock look and I figure the 850 to 1050 cfm would out perform the six pack but again that is just my lack of knowledge of the six packs. Very cool just not something I had considered
                   
                • Rocketman

                  Rocketman Well-Known Member

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                  I have a Holley 3310 750 cfm on a modified 440 ground to .060 over. Edelbrock top end kit, Comp .545 lift cam, and MSD ignition. It is the perfect carb for me. My dyno tuner says ideally a 770 cfm would be best if I was racing, but this is a street machine. He said 850 cfm would waste money and fuel.
                   
                • 5.7 hemi

                  5.7 hemi FBBO Gold Member FBBO Gold Member

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                  Fuel injection....nough' said!
                   
                • 747mopar

                  747mopar Well-Known Member

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                  I'm running an 850 Street Demon DP on my 456" and like it, there are better ones with more tuning options like the mentioned QuickFuel but I just feel the Demons are the best bang for the buck at $450.00ish. I personally won't run a carb without a choke (takes 2 people to start the car in cool temps haha) so that's why I run the Street Demon and buy the choke kit.
                   
                • 65Fury440

                  65Fury440 Well-Known Member

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                  I have an 850 Mighty Demon with annular boosters and love it.
                   
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