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Technical Small block Ford clutch sizes

Discussion in 'The Hokey Ass Message Board' started by junkyardjeff, Apr 5, 2015.

  1. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,909

    junkyardjeff
    Member

    My custom 500 that has 289 clutch parts that I think has a 9 1/2 inch disc which only got me 30,000 miles,so that got me thinking that maybe I should find a flywheel from a truck or possibly newer 302 powered vehicle that will get me a slightly larger disc that might last a little longer since a 9 1/2 disc in a full size car seems a little small. I have a 65 289 flywheel on a 70 302 and if I go with a bigger clutch it must fit in my existing flywheel since the Z bar ball screws in the bellhousing and I think no other small block bells have that,so has anyone went to a slightly larger clutch on the SBF then what came originally.
     
  2. 61falcon
    Joined: Jan 1, 2009
    Posts: 772

    61falcon
    Member

    i have a 10.5 inch clutch in my Falcon. 302 with a T5. newer 302 flywheels have a different balance. starting in '86 the balance changed to 50oz. prior to that they were 28oz. there are 164 and 157 tooth flywheels. my flywheel is an aftermarket aluminum sfi rated but there are less expensive steel flywheels that will except a 10.5 clutch.
     
  3. fordor41
    Joined: Jul 2, 2008
    Posts: 946

    fordor41
    Member

    my '81 is a 50 oz .
     
  4. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,909

    junkyardjeff
    Member

    In a couple weeks I am going to hit the junkyard and look at manual trans 1980 and older trucks and see what I can come up with. Since its been many years since I had a manual trans vehicle that was driven frequently is 30,000 miles good life for one driven about 50 percent around town,it seems low to me and I know everyone is different on how they drive so its hard to tell but was hoping for a little longer life out of the clutch.
     

  5. birdman1
    Joined: Dec 6, 2012
    Posts: 1,184

    birdman1
    Member

    have you tried a 10.5" clutch on your flywheel? It should fit. If it will not take a bigger disc, get a better quality disc for the small clutch and run it. If most driving is around town, and you drive it like most hot rodders do, 30,000 miles is doing okay.
     
  6. mjlangley
    Joined: Dec 11, 2008
    Posts: 170

    mjlangley
    Member
    from SE MI

    30k miles doesn't seem that bad if you have lower (numerically) rear gears.

    9.5" sounds small for a 289, I thought they used a 10" for the base and 10.5 for the high-perf applications. How many bolt patterns does your flywheel have drilled into it?
     
  7. mjlangley
    Joined: Dec 11, 2008
    Posts: 170

    mjlangley
    Member
    from SE MI

    Sorry premature post....

    I asked about the flywheel as some have multiple bolt patterns drilled into them and you can upgrade.

    SBF flywheels come in two sizes: 157 tooth and 164 tooth. The larger usually found on 351W engines, and requires a larger bellhousing as it sounds like you are aware...

    Here is a replacement flywheel showing the two bolt patterns, if yours is the same, I think you can move up to a 10.5" clutch pretty easily:
    SBF Flywheel.JPG
     
  8. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,909

    junkyardjeff
    Member

    I can not remember if the flywheel multiple sets of holes so it looks like I will need to tear it apart before buying any parts,the shop that sold me the clutch parts sold me a diaphram pressure plate that I absolutely hate and has been too stiff from day one so it will be going back to the original style pressure plate. I think that too stiff pressure plate along with my left ankle that was severely twisted many years ago could be a cause for what I think are too few miles on the now slipping disc,it could be a 10 inch disc since its been over 10 years since I put it togather.
     
  9. Relic Stew
    Joined: Apr 17, 2005
    Posts: 1,136

    Relic Stew
    Member
    from Wisconsin

    Trucks came with the 164 tooth flywheel with an 11" clutch. Compact cars like Falcon and Mustang had the 157 tooth with 10" or 10.5".

    The 300 six also uses the small block bellhousing and crank flange bolt pattern, but the flywheel has neutral balance.
     
  10. IIRC, the truck 11" SBF clutch bell is cast iron and quite a bit bulkier. And it's fairly rare, I've only seen a few over the years.
     
  11. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,963

    seb fontana
    Member
    from ct

    Diaphram Pressure Plate should not be that hard on the foot, should be way easier than a Long style/Borg&Beck three finger of the same size/pressure rating..Are you sure clutch linkage is ok?..And I had a Aluminum bell with 302 pattern and put it on a 300 6L with an 11" clutch and had no clearance issues..
     
    Last edited: Apr 6, 2015
  12. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,909

    junkyardjeff
    Member

    Found out its a 10 inch clutch and not sure why I thought it was a 9.5,I would like to step up to a 11 inch clutch if it will fit in the bellhousing.
     
  13. finn
    Joined: Jan 25, 2006
    Posts: 783

    finn
    Member

    The diaphragm style pressure plate will give lower pedal pressure, so that's what you want.

    The old long style in my Mustangs and van got old in heavy traffic.
     
  14. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,909

    junkyardjeff
    Member

    Found out a early 70s F100 with a 302 had a 11 inch clutch so I am going to hit the junkyards and see if there are any so in case I need a flywheel,I will have to disagree on the diaprham pressure plate requiring less pressure since it and the 67 skylark both had those pressure plates and would hurt my foot in heavy traffic. A friend had one in his 64 galaxie and when the throw out bearing destroyed the pressure plate we put a long style back in and it was much easier to push in the clutch.
     

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