Converting to Tach gauge cluster

1975 - 1979 Mopars

  1. d9103365

    d9103365 Well-Known Member

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    My 75 Fury Sport has the standard gauge cluster...including an idiot light for the oil pressure instead of a gauge. I want to convert this to a cluster that has the tach. I've been gathering parts for a long time. As you know, all of the gauges have to change out except the speedo - i have them all, including the tach. I also have the necessary bezel and an NOS circuit board that goes behind it. I'm thinking that all of this should pretty much plug right up. Is there anything else that would have to be modified to make this setup work? I'm guessing I'll have to run some kind of line for the tach, but not sure if the new circuit board takes care of that or not. I'm assuming that the same harness connections will operate the different gauges. Any comments?
     
  2. marty mopar

    marty mopar Well-Known Member

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    circuit board #3592894 1975 R,W,X,S used /tach

    R,W,X,S = Fury, Coronet, Charger, Cordoba

    may fit other years
     
  3. RWG75

    RWG75 Well-Known Member

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    I've done this swap on my 75 Charger and one of the 76 Daytonas. The tach vs non tach circuit boards are plug compatible. The circuit board for the uber rare clock where the tack sits will also work for the tach set up. If you want to verify, just lay the circuit boards out and trace the runs from the connector to the component.

    I recall changing the larger carrier for the gauges / hvac control / radio on one of them but not so sure about the other. Probably because the tach is deeper and the carrier has a hole cut out for it.

    Nothing for the tach is in the stock harness so you have to add power, ground and coil. The bulkhead disconnect has a cavity reserved for the coil lead (see FSM wiring diag).

    I wired the power for the tach to some available 12v lead under the dash, probably per the FSM diag. Dumb thing here is that when the alt is charging the battery, it's more like 14v so the tach reads a 1,000 rpm or so high - no limiter like the other gauges. Other annoying thing is that the needle pretty easily disconnects from the movement but ya can pop the needle cover off and reconnect it. Have had this happen to at least 3 tachs.

    I also managed to snag a couple cop certified 140 mph speedos for them!
     
  4. Micah Pohlman

    Micah Pohlman Active Member

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    It sounds like you have all you need. All you should have to do is run a wire from the coil to the bulk head connector and get it in the right slot. Find a factory service manual wiring harness section to get the right location. Every dash side harness I've dealt with has the wire in it for the tach, so just the engine side add is needed.
     
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