Poor mans electronic speedo conversion

Discussion in 'Gauge Marks' started by supwicha, Aug 20, 2015.

  1. supwicha

    supwicha Veteran Member

    160
    3
    Feb 23, 2014
    Victorville, CA
    Hello all, looking for some suggestions/feedback on my cluster project. I have recently converted my '79 to a later model EFI LT1 setup from a Caprice. In an effort to control cost, I did not want to change tailshaft housing to have a VSS signal at $500. I also wanted to maintain the stock cluster appearance. I gutted the sppedometer head and updated it with components from an '05 Chevy Aveo and will use the original PCB wired to the PCM. I should be able to update the decal for a perfect match although it is surprisingly a close match. I should also be able to update the calibration via the PCM. Has anyone ever tried this type of conversion before? If so, how did it work out for you? So far I'm into it for $18.

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  2. Da-bigguy

    Da-bigguy Veteran Member Lifetime Gold Member

    3,049
    22
    Jan 19, 2010
    Cypress, TX
    That looks pretty good. Have you got it installed and running yet? I'd like to know how that goes.
     
  3. harbone66

    harbone66 Veteran Member Lifetime Gold Member

    3,302
    185
    Feb 15, 2011
    Central Illinois
    Nice work, heck it even kind of matches!
     
  4. supwicha

    supwicha Veteran Member

    160
    3
    Feb 23, 2014
    Victorville, CA
    I do not have it installed yet. I still have about 25 hours more of work to complete my LT1 conversion. As well as some other miscellaneous items. I figure I'm 6-8 weeks out before I resume the cluster project. I'll update when I get there, thanks for your interest.
     
  5. cvhu

    cvhu Member

    97
    4
    Jan 18, 2012
    sarnia, ontario, canada
    i used the same speedo for my conversion, it works but its off by 10 kms per hour
     
  6. supwicha

    supwicha Veteran Member

    160
    3
    Feb 23, 2014
    Victorville, CA
    Have you attempted to modify the calibration in your PCM? Thanks
     
  7. hogg

    hogg Veteran Member

    3,083
    24
    Dec 29, 2000
    pegram,tn.,cheatam
    Can't you just move the hand?
     
  8. supwicha

    supwicha Veteran Member

    160
    3
    Feb 23, 2014
    Victorville, CA
    Most likely he is describing an issue related to accuracy over a various range of speed and not a needle being stuck at a certain position. Electric speedometers normally self center at zero at startup. It may be that the pcm needs the correct tire/gearing combination to work.
     
  9. cvhu

    cvhu Member

    97
    4
    Jan 18, 2012
    sarnia, ontario, canada
    supwicha is correct the accuracy is off by 10kms but i am working on a way to fix it
     
  10. 80sz

    80sz Veteran Member

    2,153
    143
    Feb 2, 2014
    Buffalo,n.y.
    Can you put stock pointer on new spedo? Looks nice
     

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