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Thread: 343 flexplate?

  1. #1
    Bulltear forum member New to the forum
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    343 flexplate?

    so i bought another jeep.... (that makes 4 legally owned cj7s at this moment, all amc powered) and it has a 343 with a manual 3 speed and a dana 20. my intentions for this one is an off road beast. id like to beef up the 343 so about 500hp (unrealistic?) and have an automatic behind it with either a dana 20 or 300. was there ever a vehicle from amc that had a 343 with an automatic from the factory? or is there a custom route that im going to have to travel to accomplish this goal?
    thanks




    Jeeps and girls are alot alike, both get mad when you call them the "c word", both like to be rode hard, both of them are hard to control... Hell, the only difference between them is you can only fix one with a hammer

  2. #2
    Thank you from BT ULTIMUS MAXIMUS STATUS tufcj's Avatar
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    The only automatic that was behind a 343 was a Borg/Warner in AMC/Rambler cars. The crank will have to be removed/machined, or an adapter used to mount a TH400 or TF727. Novak and maybe Advance Adapters also make an adapter for the 700R4.

    AMC v-8s are externally balanced, so whatever flex plate you use will need to be match balanced to your current flywheel so you don't get vibrations. You might be better off to swap in a 72-up 360. A few more cubes, better heads, and the crank is already machined for the later automatics.

    Bob
    tufcj
    1969 AMX
    1967 Rambler Rogue

    If you need a tool and don't buy it...
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    and not have it.
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  3. #3
    Bulltear forum member New to the forum
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    i do agree that a 360 would be a better and easier swap but i already have a cj with a 360. iv always thought it would be cool to have a 343 in a cj, you just don't see it. i have a friend with an 80 amx that is interested in trading a 360 with 390 heads on it for the 343 i have but he says he wants to run an automatic too so regardless id still like to be able to find one i just have no idea where to start looking of one……
    thanks

  4. #4
    Thank you from BT ULTIMUS MAXIMUS STATUS tufcj's Avatar
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    A 360 with 390 heads isn't really a great combo either. While you do pick up .5 to.75 in compression, you lose any gain in the poor flow of the square port heads. The 360 head has the same size intake and a slightly large exhaust valve, plus a much better flow rate. The pre-72 cranks can be machined for the later trans, you just have to pull the motor apart. I think the machining directions are posted somewhere on Bulltear. If not, I can post them.

    Bob
    tufcj
    1969 AMX
    1967 Rambler Rogue

    If you need a tool and don't buy it...
    you'll eventually pay for it...
    and not have it.
    Henry Ford


    Vote for BULLTEAR on top4x4sites.com ===> VOTE BUTTON

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