69 1/2 a12 mcode

A12 Mopar Discussions

  1. 63fury500

    63fury500 Well-Known Member

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    I got into a riff with someone on a facebook page who said the 69 1/2 a12 cars did not come with the sixpack rods and balancer until 70,i told hime he was full of it,am I correct in saying that all a12 m code cars in 69 had these
     
  2. R/T Boy 67

    R/T Boy 67 Well-Known Member

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    You would have lost money,if you made a bet.
     
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    • 33 IMP

      33 IMP Well-Known Member

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      Yep. 69 1/2 A12 sixpack cars had ordinary LY rods. Maybe magnafluxed or specially selected.... but the fat sixpack rods didnt show up till 70.
       
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      • 63fury500

        63fury500 Well-Known Member

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        wow,im lucky i didnt bet,i was always told in articles and by people the 440 six pack motor had the six pack rods,the balancer and the notched pistons,different profile cam,so they were wrong?was every 69 1/2 reg ly rods?and just a different top end???
         
      • R/T Boy 67

        R/T Boy 67 Well-Known Member

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        All HP 440s, four or six,had the big rods in 70 and 71
         
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        • gtx6970

          gtx6970 Well-Known Member

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          To the best of my memory, the only thing different over a 4 bbl 440 hp ,,,,,is the intake, carbs and air cleaner
           
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          • 63fury500

            63fury500 Well-Known Member

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            here is more i came up with
            The Six Pack package included more than just a unique intake and carburetor setup. Beefier connecting rods (and an appropriately weighted harmonic balancer), moly-filled top rings, a revised, low-taper camshaft, flat-face hydraulic tappets, chrome intake and exhaust valve stems with valve springs lifted from the Hemi and a bump in compression from 10.1:1 to 10.5:1 all helped boost the output of the 440 to 390hp and torque from 480-lb.ft. to 490-lb.ft, a number identical to that of the Hemi, but delivered a full 800 RPM sooner in the rev range. All A12s were also equipped with a 4.10:1 rear axle, along with a dual-breaker distributor, heavy-duty radiator, heavy-duty 11-inch drum brakes and "extra-fat" Goodyear 15-inch Polyglas red stripe tires.
             
          • droptop

            droptop Well-Known Member

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            Isn’t the cam different on the six barrel engines also?
             
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            • 63fury500

              63fury500 Well-Known Member

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            • 63fury500

              63fury500 Well-Known Member

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              Does anyone on here have the real specs on the a12 m code???
               
            • toolmanmike

              toolmanmike Moderator Staff Member FBBO Gold Member

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              The 69 1/2 rods are described as "Same as 440 except 100% "Magnaglo inspected". The 69 440-6 and 1970-72 440-6 connecting rods are not the same; hence a 1969 440-6 engine does not have 6-pack rods."
               
            • 33 IMP

              33 IMP Well-Known Member

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              My numbers matching a12 engine is on a stand in my garage (theres a 511 in the car). When i get a chance to pull it down, i will document what i find.
              I can guarantee that it has a neutral balancer on it, therefore LY rods.
              I am curious about the low taper cam. REAL compression ratio is a curiosity too.
               
            • gtx6970

              gtx6970 Well-Known Member

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              To be brutally honest.Im not sure. The A12 cars never really interested me like they do others .

              I want to remember they rods were hand picked , maybe different cam and heavier rocker arms.
              Or all this might be a 1970 thing
               
            • 69 MBee

              69 MBee Well-Known Member

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              http://sixpacksixbbl.homestead.com
              The absolute best source for A12 specs. From there it's over to the lift off playground!
               
            • 33 IMP

              33 IMP Well-Known Member

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              Personal experience says that is mostly correct...., except for the "beefier rods" and the question of compression ratio in 69.
              There have been marketed "six pack pistons" that have valve reliefs and a taller compression height than ordinary 440 pistons, but i dont yet know what is in my 69 motor. Sixpacks had a higher "advertised" compression than the regular 440 in 70/71.
               
            • R413

              R413 Well-Known Member

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              1969 A12 had LY rods, a 402 oil pan, no skid plate on the K frame. They had a “low taper” cam and lifters. Whatever that means.

              All the other stuff came in 1970. 6pk rods, hemi pan, skid plate.
               
            • slimt

              slimt Well-Known Member

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              Back in the day. We didnt care. We just drove those like we stole those. Pedal to the metal and gone. :)
               
            • Richard Cranium

              Richard Cranium FBBO Gold Member FBBO Gold Member

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              • fastmark

                fastmark Well-Known Member

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                I’ve owned two A12 and both had original motors. I still own one with 23,000 miles on the clock. I have the crankshaft from the other one still. I own a 70 model Superbird with the original 6 pack motor complete. I have two other 70 model cars with 440 Hp motors, both original. I have torn apart many motors over the years and have lots of parts. So, here’s the facts. I do not post it unless I know it.
                69 A12 had std weight rods and the same piston as any 440 hp. It had the special low taper camshaft, as mentioned, but I can’t verify from my cars if that was the same three bolt as the three bolt in my 70 Bird. My Bird had the original camshaft. I could look in the parts book for that. The 69 440-6 also had a different “ Premium” chrankshaft different from the 4 barrel, even though they shared the same rods and pistons. It was internally balanced. It has a forging number of 2208160( from my memory). The same Premium crankshaft was used in the 70 440-6 as well, even though the motor was externally balanced. The 70 440-6 had the “heavy” rods, commonly and mistakenly called “six pack rods”. Just like my super bird is a 440 “six barrel” but called a “six pack” by the masses. The 70 440-4 hp had the same “heavy rods” and slightly lighter lower compression pistons, the same external balancer but a different crankshaft than either of the two above. Confused? So are most people. Now throw in the fact that some truck motors in the mid 70’s had “ heavy” rods, low compression pistons and internaly balanced! Even more confusing is the fact that some 440 hp motors I have taken apart had this same forging number stamped in the forging. 2208160 does not always mean it’s the “ Premium shot peened crankshaft. Oh. All of these 2208160 Premium shafts I’ve had, already had a pilot bearing already install even thought it was in an automatic car.
                The short answer here is, you were wrong so you buy the beer. Lol.

                One thing to add for clarity. The 2208160 forging is the forging number. After it is machined, it gets a part number. So the 2208160 Premium forging could have been machined and balanced to the 70 lighter pistons of the 70 hp 4 barrel and got the 4 barrel part number and install in a 4 barrel.
                 
                Last edited: May 13, 2021 at 5:54 AM
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