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Model-A.org

The Place for Model-A Ford Carburetors

Main Bolt

Main Bolt
  • The Main bolt has 3/8-24 UNF (SAE) threads.
  • The hex head width was 1/2" through 1928. Thereafter, it was 9/16".
  • The Hex head thickness was 5/16" through mid 1930 and 1/4" thereafter.
  • Bolts were Cadmium or plain finished.
  • A lock washer is used with the bolt.
  • Bolts were originally 3 inches long.
  • When restoring carburetors I prefer to use 3-3/16" bolts, since casting threads are sometimes damaged for the first 1/4".

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