1980 Speedo Swap question

Discussion in 'Gauge Marks' started by Valentin80Z28, Apr 9, 2015.

  1. Valentin80Z28

    Valentin80Z28 New Member

    4
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    Apr 9, 2015
    Fort Riley, KS
    I have a 1980 Z28 with the 85MPH speedometer. According to what I've read I can't just change the speedometer to a 130 or 150. I'm wondering has anyone ever done a swap from the 85MPH to higher. Because apparently even the fuel guage isn't compatible. Do I have to change the circuit board and all the gauges? Because if so, that begins to get a bit pricey for a "let's see if this works" type of deal. Please help.
     
  2. Twisted_Metal

    Twisted_Metal Moderator Staff Member Lifetime Gold Member

    25,260
    284
    Feb 26, 2004
    Bloomington, MN
    Yes you can swap speedometers.

    The speedometer is entirely mechanical in an 80Z.
    (81 had a speed sensor for input to the 'puter.)

    You can remove the cluster and replace the speedometer with any one from 70-79.
    Connect the cable and go. :cool:

    The 85, 130 and 150 MPH speedometers GM used back in the day were all mechanically calibrated to 1000 cable revs per mile.

    I swapped a 130 MPH speedometer(from a 79) into my 80 without having to change speedometer gearing. :D

    However... I did have to change the speedometer gears in the transmission when I swapped rear end gears. That's a separate issue.


    Only the 79 speedometer has the 130 MPH top end AND the correct needle to match the rest of them in a 79-81 cluster.

    If you have dummy lights instead of gauges... You can swap to a gauge cluster and rearrange some of the wires in the cluster plug to get it done that way too.
     
  3. Valentin80Z28

    Valentin80Z28 New Member

    4
    0
    Apr 9, 2015
    Fort Riley, KS
    Thanks

    Thanks. I appreciate the info. I had no clue why the techs at classic industries told me it wouldn't work. Guessing they just meant that it wasn't original. Thanks again.
     
  4. sovain

    sovain Veteran Member

    675
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    Sep 12, 2008
    cambridge,ontario
    now I got to go and find a 79 victim... err I mean donor!
     
  5. joegunn12

    joegunn12 Member

    48
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    Jan 13, 2014
    New Martinsville, WV
    I just did this swap 85mph on my 80z to a 130 from a 79. the 79 needles match the rest of your setup...contact MRFBODY on here he may have one for you, that's where I got mine from,,,,,he's a good guy and will get it out to you pretty quick
     
  6. joeparamonkey

    joeparamonkey Member

    60
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    May 17, 2012
    San Antonio, TX
    Great info like always. just got me a 130 on ebay.
     

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