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engine block identification by block plate

Discussion in 'Intermediate CJ-5/6/7/8' started by rholmes69, Sep 16, 2015.

  1. Sep 16, 2015
    rholmes69

    rholmes69 goat herder....

    Raleigh NC
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  2. Sep 16, 2015
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Almost. In your case, 6 is 1973. The rest is the same. Look at the 1974 FSM at http://oljeep.com/edge_74_tsm.html in the section on 6-cylinder engines.

    What's the build date for the Jeep? It's on the yellow sticker on the dash. July of 1973 is not a surprising engine build date for an early 1974 Jeep. The model changeover happens around September of the previous year.
     
  3. Sep 16, 2015
    rholmes69

    rholmes69 goat herder....

    Raleigh NC
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    The yellow sticker is gone. The vin plate on the jeep firewall decipher as being a 258 engine.... I guess I should see if the plate in the firewall matches what is on the frame
     
  4. Sep 16, 2015
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    It's definitely a 232 block. The only difference in the 232 and the 258 is the crankshaft stroke. They have different pistons, but the same bore with different heights to accommodate the stroke.

    If the VIN says "A" then either you've a busted VIN or the Jeep was delivered with a 258. I would compare the VIN with the sequential serial number stamped into the frame near the right front shock mount. If they match, the motor has been changed.

    Note that Jeep changed the way that the blocks are numbered in 1981 - restarting the series with "1." Also, the 232 was discontinued for domestic sale sometime in the late 70s, so unless you have an engine from an import or agency vehicle (ie mail truck or some such), it was shipped in 1973.
     
    Last edited: Sep 16, 2015
  5. Sep 16, 2015
    rholmes69

    rholmes69 goat herder....

    Raleigh NC
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    Is the serial on top of the frame or on the sides? Have some undercoating to scrape away, didn't want to waste too much time in the wrong place.... there is a lot of it....
     
  6. Sep 16, 2015
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Top AFAIK. Maybe I can look at mine in daylight.
     
  7. Sep 21, 2015
    nwedgar

    nwedgar Now with TBI!

    Newnan, Georgia
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    Yep...top passenger side kinda near the shock mount, as Tim noted.
     
  8. Sep 21, 2015
    rholmes69

    rholmes69 goat herder....

    Raleigh NC
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    Well not that anyone but me was holding their breath, but the serial on the frame matched the vin plate on the firewall. It was indeed on the top of the frame forward of the shock tower towards the front bumper. Had to wire brush off a lot of some sort of coating. Was very pleased to find the metal underneath very bright and clean. Now I wanna know why in the world a 232 is in there.....
     
  9. Sep 22, 2015
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    It's a replacement engine. The most likely scenario is the PO was short on cash, the original engine needed major work, and a junkyard 232 is cheap. They bolt in, just like a 258. There is nearly zero demand for a 232 today.

    If I wanted to swap it, I would skip the 258 and go with a 4.0L replacement from a '91-on YJ or XJ. The 4.0L HO is an easy swap, and it has almost as much power as the 360 - even the pre-91 4.0L will be a big step up from the 232.
     
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