exhaust header bolt size

Discussion in 'Big Block Cadillacs' started by christopher mcnicoll, Aug 9, 2017.

  1. christopher mcnicoll

    christopher mcnicoll New Member

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    What vehicle(s) do you drive?:
    T bucket
    hi there, could someone tell me the exhaust header bolt size please, got a few snapped bolts and will need to get them drilled and tapped.

    thanks

    chris

    1970 cadillac 472
     
  2. Cadiac

    Cadiac Active Member

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    3/8" course thread
     
  3. christopher mcnicoll

    christopher mcnicoll New Member

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    Is that 3/8---16? I know we all have different thread names here in the uk
     
  4. Darius

    Darius Well-Known Member

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    Hello Christopher,

    Yes, we here in the colonies consider "course" thread, in 3/8 size, to be 16 threads per inch.

    https://www.boltdepot.com/fastener-information/measuring/us-tpi.aspx

    https://sizes.com/tools/thread_american.htm

    In the past I've had good success using either stainless steel or brass studs - or nuts, that in an attempt to avoid corrosion problems. Also, for purposes of tighter clamping forces, the thread going into the head are "course" while the outer threads are "fine."

    Hope that helps.

    Best,

    Darius (bro d)
     

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