Timing on a 401 engine

Discussion in ''Da Nailhead' started by staged67gspwr, Nov 1, 2002.

  1. staged67gspwr

    staged67gspwr "The Black Widow"

    Was wondering what the timing is suppost to be set on a 401,initial and total,i know on the 400-430-455 about 34 degrees total is good.


    Thanks
    George
     
  2. Babeola

    Babeola Well-Known Member

    Nailhead Timing Curve

    George,

    The Stock Nailhead curve is 28-32* of mechanical advance at the crank all in by 3900 rpm with 2.5* of initial timing for a total of 30.5-34.5*. The mechanical advance starts from 600-800 rpm. Here are three performance Nailhead curves to pick from:
    • Old Nailhead Site Curve: 22* of mechanical advance at the crank all in by 2200-2500 with 8-10* of initial timing for a total of 30-32*.
    • Mallory Nailhead Curve: 15* mechanical advance at the crank all in by 2800 rpm with 17* of initial timing for a total of 32*. The mechanical advance should start at 1000 rpm.
    • Carmen Faso Nailhead Curve: 18* mechanical advance at the crank all in by 3000 with 14* of initial timing for a total of 32*. The mechanical advance should start between 800 and 1000 rpm.
    The curves need to set with the vacuum advance hose off and plugged. You could also have your local speed shop set the curve on the distributor machine. Manual transmissions can use earlier mechanical advance curves to their advantage with throttle control. You will have to find the set up that makes your car happy under load without pinging. Once that is established you can plug the vacuum advance back in and make sure it does not add too much advance under part throttle applications. An adjustable vacuum advance or a stop will be needed if vacuum advance makes it ping.

    Cheryl :)
     

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