300 Harmonic Balancer Diameter?

Discussion in 'Small Block Tech' started by Matthew Taylor, May 17, 2020.

  1. as the title says, anyone know the standard diameter?
     
  2. TrunkMonkey

    TrunkMonkey Totally bananas

    Lemme go measure.
    BRB.

    6.5 inches

    1964 Skylark 2bbl, st300 no air.
     
    Last edited: May 17, 2020
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The 350 and 400-430-455 balancers are 6.75" in diameter. I thought the 300's were the same.
     
  4. TrunkMonkey

    TrunkMonkey Totally bananas

    Let me go measure the circumference.
    Pulley made of a challenge to get parallel straight edges and measure across the face.
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Should be a bit over 21"
     
  6. TrunkMonkey

    TrunkMonkey Totally bananas

    Yes. 21.20 is what I got.
    So, 6.75.
    Thanks. :)

    If the pully was out of the way, I could have made a better measurement. Trying to hold two straight edges and a tape measure. Three times and I got 6.5 each time.

    I threw my straight edges and tape measure in the trash.
     
    Mart likes this.
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Very good Mike, thanks for double checking.:)
     
  8. Yeah I measured, it's not a stock balancer on my 300. 7.25 here. So there's a jerry rigged ford balancer on mine with the part number stamped on it. Guess that's getting replaced. LOL

    Also note: I have no damn clue how it happened. It fits, the crank isn't shaved and there's nothing wrong with the woodruff key, all in the stock place according tot he service manual. BUT iit explains my difficulty timing the sucker.
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Well, if you want to time it temporarily with a 7.25" balancer. You can measure 2"clockwise (facing the front of the car) from the stock mark, and make another mark. That is approximately 32*.

    7.25 X 3.1416 =227766,.............. 227766/360 = .06327............. 32 X .06327 = 2.024"
     

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