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Underdrive pulley

Discussion in '1994-2004 V6 Mustang Tech' started by 20003.8stang, Mar 4, 2018.

  1. 20003.8stang

    20003.8stang Member

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    I'm in the middle of my m112 build and I have a underdrive crank pulley that came with my kit. I'm unsure if it's 25% or 42% does anyone know the diameter of the two so I can check?

    Thanks in advance!
     
  2. 6 Shooter

    6 Shooter Well-Known Member

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    Stock diameter of a crank pulley is 7 inches.
     
  3. 20003.8stang

    20003.8stang Member

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    So I measured mine and it's around 5.5" so that would make it 25% I think I'm going to run a 3.4" quick change pulley. I emailed billetflow to see if they have that. Any idea what psi that would be with factory heads?