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    Results 1 to 9 of 9
    1. #1
      Join Date
      Apr 2008
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      71

      Do they make a 2.73 gear for a ford 9"

      our transmission is a 1:1 ratio in final gear and a 2.73 would give us more comfort than the 3.00 gear at tracks like road america that are really fast. Need to run the 33 spline wavetrac diff, anybody know if it's made?

    2. #2
      Join Date
      Apr 2001
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      Pretty sure the highest gear ratio available is a 3.00.

      Andrew
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    3. #3
      Join Date
      Sep 2004
      Location
      Arizona
      Posts
      220

      Yes

      Not popular with most folks, but they are around.
      Attached Images Attached Images  

    4. #4
      Join Date
      Apr 2008
      Posts
      71
      Quote Originally Posted by oleyeller View Post
      Not popular with most folks, but they are around.
      Awesome! Thanks!

      Our car with a 1:1 final drive on trans can only hit ~155 with a 3.00 gear. That won't work on tracks like road america. a 2.73 will get us to 170mph and a 2.50 will get us 190mph

      Am I missing something here? I'm relatively new to racing and it seems like a lot of guys are running a 1:1 final drive transmission and running faster tracks. What are most people doing?

      Running a 27" tire, 6000rpm, 1:1 trans final gear on our car.

    5. #5
      Join Date
      Oct 2004
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      2,413
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      I do recall the 2.75 was an OEM ratio. Looking on Summit and Randy's didn't show under 3.00, so might not be available aftermarket. If you have to get used, maybe see if CompCams still offers their Nitriding service for Ring and Pinions, as added insurance.

      Red Forman: "The Mustang's front end is problematic; get yourself a Firebird."


    6. #6
      Join Date
      Dec 2006
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      Moving from Burbs of Detroit to my native homeland, the woods of Cascadia
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      Quote Originally Posted by darkostoj View Post
      Awesome! Thanks!

      Our car with a 1:1 final drive on trans can only hit ~155 with a 3.00 gear. That won't work on tracks like road america. a 2.73 will get us to 170mph and a 2.50 will get us 190mph

      Am I missing something here? I'm relatively new to racing and it seems like a lot of guys are running a 1:1 final drive transmission and running faster tracks. What are most people doing?

      Running a 27" tire, 6000rpm, 1:1 trans final gear on our car.
      I'm going to be guessing here, that most people running 170 -190 are doing it at higher than 6000 rpm. Don't KNOW that's the case, but that would be my guess.

      But what do I know- I used to run an MGB
      Greg Fast
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    7. #7
      Join Date
      Feb 2012
      Location
      compton IL
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      159
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      Quote Originally Posted by Twentyover View Post
      I'm going to be guessing here, that most people running 170 -190 are doing it at higher than 6000 rpm. Don't KNOW that's the case, but that would be my guess.

      But what do I know- I used to run an MGB
      i agree, i would seek more rpm and a taller tire.
      1965 mustang fastback. a pro-touring concoction of oem, race & custom fab...build thread here https://www.pro-touring.com/threads/...Racesteed-quot
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    8. #8
      Join Date
      Dec 2011
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      Planit Oahu, Hawaii if you don't belive me check shipping prices
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      Not only will the gear ratio, tire size, and HP goes in to figuring top speed. I would hope that I’m stating the obvious to you that there’s also drag, weight of car, rolling resistance.
      GTS (Google that ****) bench racing conciliator, Lots of stuff can go in to bench racing.

    9. #9
      Join Date
      Oct 2004
      Posts
      2,413
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      Quote Originally Posted by FlyDoc View Post
      Not only will the gear ratio, tire size, and HP goes in to figuring top speed. I would hope that I’m stating the obvious to you that there’s also drag, weight of car, rolling resistance.
      GTS (Google that ****) bench racing conciliator, Lots of stuff can go in to bench racing.
      Agree with others. There's times where a lower gear can actually reduce your top speed because the power at the rpm is not sufficient to overcome the loss factors FlyDoc listed above. Plus, since it slows down your acceleration, so you might run out of straight-away before topping out.

      I'd start with what you have and try to run some more rpm. For example, if you're power curve would allow you to run up to 7k for the short time you'd be at top speed, you'd theoretically get another 25mph or so. This will be more responsive accelerating off the corners. And then if you still find yourself rpm limited, consider the 2.75.
      Red Forman: "The Mustang's front end is problematic; get yourself a Firebird."