1974 Hei

Discussion in '1974 Specific' started by Chet 74, Sep 24, 2012.

  1. Chet 74

    Chet 74 Member

    31
    0
    Aug 7, 2012
    Santa Fe, NM
    Nasty Z28 Spotters Guide states the 1974 Z28 got the HEI mid season. Does anyone know exactly what midseason is? My car has a Vin ending in 165330 and a 02C build date which would have made this a mid to late February car and it does not have the HEI. Is this correct?
     
    Last edited: Sep 25, 2012
  2. Jonesy

    Jonesy Veteran Member

    421
    2
    Jun 7, 2008
    Minnesota
    Mine is 03C and it doesnt have HEI. Mid season is wrong.
     
  3. Z28PILOT

    Z28PILOT Veteran Member Lifetime Gold Member

    2,015
    13
    Oct 8, 2009
    Emerald Isle , NC
    It is pretty safe to say your car would not have had HEI ignition as a Feb 2C car. AS Jonesy said , it occured much latter. Midyear was the announcement , but when changes actually occured is not that accurate. Something like the last three months of production the best I can tell from cars I've observed. (just a guess):) 3000 or so cars were built with it.

    Also for example.. GM announced the Warner Trannie as midyear across the board, but my 74 Corvette was built in mid- April and has its born with Munice M21 , not a Warner. I guess they used up stuff , and was only a guess themselves when supplies would actually run out.

    We do know, At some point the Z28 engine suffix codes changed from the older 1973 codes, to the CMS & CMT suffix series. 50 state compliant emmisions .

    My observation s so far seems to indicate that all the HEI cars have these latter suffix codes.
     
    Last edited: Sep 26, 2012
  4. Double J

    Double J Veteran Member

    409
    15
    Jan 23, 2008
    Michigan
    My 74Z vin is 228705 June 18th build car w/HEI
     
  5. Jonesy

    Jonesy Veteran Member

    421
    2
    Jun 7, 2008
    Minnesota
    My 3rd week of March car is 179503, non HEI, V0307CLJ
     
  6. danbrennan

    danbrennan Veteran Member Lifetime Gold Member

    2,762
    15
    Mar 13, 1999
    Brighton, MI
    I don't have the VIN with me, but my dad brought home our '74 Camaro(which he ordered) in early June, and it did not have HEI.
     
  7. Double J

    Double J Veteran Member

    409
    15
    Jan 23, 2008
    Michigan
    That's very interesting, this got me thinking we had this HEI thing narrow down to a couple of weeks. So I went back to look at the build date of my car it's 07A I believe this translates to the first week in July the original date I gave June 18th . That's the date the engine was built. Any more information you can share the great.
     
  8. Z28PILOT

    Z28PILOT Veteran Member Lifetime Gold Member

    2,015
    13
    Oct 8, 2009
    Emerald Isle , NC
    I checked Seans Project thread, I could not find his trim tag , the thread is so long , I just skimmed it quick ..LoL ...but his engine is definelty an HEI and was assembled built 4-30CMT ..... April 30 and the CMT suffix conforms to my theory of the CMT & CMS engines codes were the HEI equipped Z28 engines.
     
  9. Double J

    Double J Veteran Member

    409
    15
    Jan 23, 2008
    Michigan
    My engine is a CMT suffix
     
  10. LT1FUN

    LT1FUN Veteran Member Gold Member

    287
    0
    Dec 5, 1999
    Chilliwack B.C. Canada
    If this helps out, I just bought a 74 HEI with stamping of 1112528 dated
    4C15.
     

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