A 430 masquerading as a 455?

Discussion in 'Wet behind the ears??' started by 69DueceQuarter, Sep 20, 2019.

  1. Hi...I just purchased a 69 Electra 225 with 13,000 original miles. She's a gem. The decal on air cleaner shows "455-4". Antique license plates boast a 455 as well. However, the engine codes (block and intake manifold) show it as a number matching 430. Perhaps the previous owner bored her to 455? How can I confirm that this may have happened? Any way to identify the current displacement?

    Great community you have here. Thanks for allowing me to ask these questions.
  2. johnriv67

    johnriv67 Well-Known Member

    At the back of the block is the 430 code that you already found. However, very few people bore a 430 out to 455 due to thinner walls of the block, but it can be done. However, you probably have a misplaced sticker on an already strong engine.

    To identify it, you could take off the valve covers and that would add even more info if you provided us the head numbers and even a picture of the rocker assembly, all which would add up more and more clues to prove it’s a 430.
  3. TrunkMonkey

    TrunkMonkey Well-Known Member

    It's a 430.
    Decals and plates are an easy attachment.

    A lot of "previous owners" have no idea what anything is.

    Likely an "honest mistake", thinking it to be a 455.
  4. flynbuick

    flynbuick Guest

    If you shine a light between the back of the intake manifold and the firewall, raised 430 numerals should be cast into the block. They face upwards.

    It is unlikely any 430 Buick engine would have the cylinder wall thickness needed to accept a bore yielding a 455 displacement. 455 Buick engines are not 430 castings that are over bored.

    The decal on the air cleaner was most likely changed. Feel the top of the decal. Aftermarket decal numerals are often not raised ("embossed"). Even if yours are embossed, the prior owner could have bought replacement original factory decals.
  5. Quick Buick

    Quick Buick Arlington Wa

    FWIW. My 400 was bored to a 430 + 30 over. Also FWIW. did sonic test the block still plenty of meat on the bone to bore it to a 455..
    Crank was toast so got a 72 455 virgin long block.
    Donuts & Peelouts likes this.
  6. flynbuick

    flynbuick Guest

    In light of core shift limitations I can find only one instance where 455 was safely reached with a 430. Gary reported that he had done this. One would need to bore a 430 another 125 one thousands to get to 455.
  7. jj5794

    jj5794 Well-Known Member

    Would it be this 1969 Electra 225?

    1969 Electra on local CL - Posted August 29 on the AACA website under Buick Buy/Sell.

    Posted in The Washington DC craigslist.

    Jim Vesely
    ROA # 7437
    BCA # 39477
  8. Indeed it is. Do you happen to know more info on the heritage?
  9. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I've heard of this before once or twice. It's rare but it does happen. This may seem strange but people lie all the time. Even without good reason about the dumbest crap.
  10. jj5794

    jj5794 Well-Known Member

  11. TJinMobile

    TJinMobile Member

    I would hope it would still be a 430. If bored that amount it would not have any rebuilds left in it if ever needed. Worst still would be having someone swap a 75-76 455. The heads are junk on those.

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