TUNING A SIX PACK

A12 Mopar Discussions

  1. mac

    mac Well-Known Member

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    the carbs i had were pretty rough and just about anything would be an improvement. also, like i mentioned before, i did not have a good experience with the Promax replacement.
     
  2. 440beep

    440beep FBBO Gold Member FBBO Gold Member

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    do you by chance have a photo of these small screws? I'm trying to visualize................

     
  3. MAPS

    MAPS Active Member

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    So you are saying i am better of putting back the 6.5 valve ?
    Thank you.
    Zoi
     
  4. 66Satellite47

    66Satellite47 FBBO Gold Member FBBO Gold Member

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    No my 6 Pak's are long gone. If you look under the base plate on the end carbs you can see the screw that sets the throttle blade position. You need to have the end carbs off to see it.
     
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    • 66Satellite47

      66Satellite47 FBBO Gold Member FBBO Gold Member

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      As you look through this thread you can see that 6 Pak's need a lot of tuning attention to run real good. The power valve should not have a real big factor at idle. Try a few. But start with the basics. Float level, idle mixture screws, main jet size. On most stock combinations the end carbs are lean, maybe not yours. Many 6 Pak's got modified back in the day, look to see if yours is one.
       
    • MAPS

      MAPS Active Member

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      Thanks I have done everthing and twice.
      My last bet is sending them out to some guy everyone swears by and see what happens there and if that is not succesful ...4 "pack"
      here I come...lol
       
    • RJRENTON

      RJRENTON FBBO Gold Member FBBO Gold Member

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      If you do not get your problem fixed and proceed with your "4 pack conversion", I'll give your old carbs s good home.....
      BOB RENTON
       
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      • 66Satellite47

        66Satellite47 FBBO Gold Member FBBO Gold Member

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        Which intake are you using, and which carbs? The '69, 70 & 71 carbs seemed to be very different in what they wanted.
        A 4BBL will likely take some work too. I spent over two months and at least 100 runs to get my 850DP and TM7 intake dialed in. No instrumentation, computers and O2 sensors back then.
         
      • BrianInTexas

        BrianInTexas Member

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        Is there anyone in south/central Texas (I’m about 65 miles west of Houston) with six pack experience that can help me dial in my car? I can adjust fuel levels in the bowls and adjust idle mixture, but I have only a little experience (rebuilt a 4 bbl and changed power valves) beyond that with fine-tuning carburetors, and no experience with six packs. My car was running well and then spark plugs fouled…I believe the front or rear carb float/needle/seat stuck open and started flooding the engine. I changed the spark plugs, checked the bowls/floats and plan to get some clear bowl plugs to set the fuel level as described in this post. However, for me to go beyond that, I’m more likely to make things worse, or as Clint Eastwood said, “man has got to know his limitations.” I’m also open to trailering my car to someone that can help. Of course, I expect to pay for this and hopefully make some new friends along the way. Thanks, and I’ll post updates after I experiment with getting the fuel level correct in the bowls. Brian
         
      • 66Satellite47

        66Satellite47 FBBO Gold Member FBBO Gold Member

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        You do need to get the float levels correct. If needed replace the needle/seats. Stock jetting is probably pretty close. I found that on the end carbs, taking the end carb idle mixture screw plugs out and richening them slightly 1/8 or 1/4 turn made a big difference. Also on the end carbs the idle throttle position has an adjustment screw below the baseplate. I found that that helped, but I had a pretty big cam.
         
      • BrianInTexas

        BrianInTexas Member

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        Thanks for the suggestions…I’m going to start with the floats and go from there.
         
      • AAR4Fun

        AAR4Fun New Member

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        I know this post is sometime back in the thread, but need to know. Were you experiencing any stumble or falter with the lower PV while the pedal is in motion and before secondaries come on? My AFR leans from mid 14's to 16's before more fuel is introduced and it comes back down. This is with only the center carb functional.
         
        Last edited: Nov 15, 2021
      • Frustration

        Frustration Well-Known Member

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        Sorry for the delay getting back to this bogging off the line, and lean condition in the 4000 RPM range. I noticed a fuel leak on my intake manifold. Not a ton, but enough to smell and a small puddle would form on the driver's side. I found out that the accelerator pump had warped due to someone (probably me) overtightening it. I put a straight edge on it, and it was considerably bowed. I used a fine file and brought it back to square. It solved the leak as well as the bog down low. It was actually pumping gas out between the accelerator pump and the carb base. It was enough to see when I took the air cleaner off. May be worth checking if you have an old set of carbs.
         
      • 68 HEMI GTS

        68 HEMI GTS Well-Known Member

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        I could see it on the A/F gauge, it felt slightly smoother with the higher number PV as well when you accelerate from a roll. Keep in mind if your vacuum outboards start to open you will see a lean spike untill the boosters turn on. No way around it.
         
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