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Trying to ID Small Block

Discussion in 'The Garage' started by jfortner, Jun 23, 2004.

  1. jfortner

    jfortner Registered Member

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    I am trying to ID the small block in my Blazer. The ID code that is stamped into it is V0121U7. I can't find any documentation for the U7.

    The heads cross as a 68-73 350, 75cc chamber heads. The intake crosses as a 74-76 350 QJet car intake.

    The engine is in a '71 blazer and the owner said it was orginal and never had any work /forums/images/graemlins/thinking.gif based on the mismatched bolts and the RTV on some of the gaskets I know it has had work... So I am not sure if this is the orginal engine or not?

    Thanks John
     
  2. highrider_44s

    highrider_44s 1/2 ton status

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    is that the number off the back of the motor on i think is on the drivers side right were the bell housing bolts onto. thats the engin id # /forums/images/graemlins/deal.gif
    the one you posted kind off looks looks the number from the front of the block /forums/images/graemlins/dunno.gif
     
  3. jfortner

    jfortner Registered Member

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    Yes, the number is off of the front. I usually cross reference this number because it tells you how the engine was orginanlly built. Compression, carb, HP, etc. I just can't find the U7 in any of my reference manuals. The number at the back of the block just isn't accessable with the engine in no matter what I try and do to get at it.

    John
     
  4. diesel4me

    diesel4me 1 ton status Premium Member

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    I've had several 1971 chevy truck motors,the number on the front of the block should have a 3 letter code after the VIN#,like TDR,TDH,TDP,those are 3 of the block codes I had on mine.The BIG casting # in back will only tell the displacement,and not specific horsepower and tranny listings,as you probably already know--if you find a code that begins with a "T" post it here--I can look it up in the original GM parts counter book I have that covers 47-72 series 10-30 trucks.Maybe the # for the heads will help narrow it down some,but they could have come of anything.
     
  5. BurbinOR

    BurbinOR 3/4 ton status

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  6. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    are you sure its says U7? i have never seen any that have numbers in the suffix.
     
  7. jfortner

    jfortner Registered Member

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    It is a fairly clear stamping and I am certian it is only two letters U7. They did use some numbers in the code for a few blocks. This is one of the better references I have found on-line http://www.nastyz28.com/spmenu.html

    Since I wasn't able to find U7 in any of my books or online I didn't know if it could be a crate block /forums/images/graemlins/dunno.gif

    Does anyone else with a 1971 have a U7 as the last two digits stamped into the pad on the front of the engine passengers side?
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    I havent seen a code that ends with a number either(yet!)--but looking at the list of codes on that site you listed,it might be UJ--that would be a 69 307,from a K series truck--maybe someone swapped an older motor in!?.
     
  9. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    thats the same one i use, i dont have a book for the codes.
    try the GM dealer /forums/images/graemlins/dunno.gif
     
  10. jfortner

    jfortner Registered Member

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    Thanks for the help, I pulled the intake and found the block ID. It places it as a 1969 307. Not what the previous owner claimed but with as bad as it smokes it needs replaced anyways. Will get me by for now.
     

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