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    Results 1 to 11 of 11
    1. #1
      Join Date
      Oct 2013
      Posts
      101
      Country Flag: Canada

      Rear gear ratio advice

      I have a 67 Chevelle with a 2006 Corvette 6.0 LS 2 in it, the trans a 4L 60 E and I plan on doing a 2600-2800 stall converter and camshaft swap. The vehicle has a few upgrades and makes around 500 hp. I’m looking for rear gear ratio advice. Wondering what a good “trade-off“ ratio is. This is a weekend car and thinking about either at 3:55 or 3:73..

    2. #2
      Join Date
      Feb 2008
      Location
      Texas
      Posts
      302
      Country Flag: United States
      I vote for 3.55:1. If it's a weekend car it will be more fun with a higher stall torque converter say around 3600-3800. I wouldn't buy one of those rebuilt converters that have the fins bent to increase the stall speed. Get a nice one like a 9" converter with a billet front cover. The shift extension will be better with a looser converter especially with that big drop from 1st to 2nd gear.
      http://www.youtube.com/user/cutlassrkt?feature=mhee
      69 cutlass - 5.3l L33, Jakes stage 3 4L80e, 275/40/17 proxes tq

    3. #3
      Join Date
      Oct 2004
      Posts
      2,544
      Country Flag: United States
      You didn't mention the camshaft. But, sounds like you won't be doing a ton of highway. I vote for the 3.73s. The .696 final drive would keep you cruising <2500 even at 70mph. Should make it really more responsive and fun even with the mild stall.

      Circle has a budget 278mm (11") 3000-3200rpm budget convertor with anti-ballooning plate. Make sure you have a large trans cooler if you're putting all the power to a 4L60E.
      Red Forman: "The Mustang's front end is problematic; get yourself a Firebird."

    4. #4
      Join Date
      Feb 2008
      Location
      Texas
      Posts
      302
      Country Flag: United States
      Quote Originally Posted by 68Formula View Post
      You didn't mention the camshaft. But, sounds like you won't be doing a ton of highway. I vote for the 3.73s. The .696 final drive would keep you cruising <2500 even at 70mph. Should make it really more responsive and fun even with the mild stall.

      Circle has a budget 278mm (11") 3000-3200rpm budget convertor with anti-ballooning plate. Make sure you have a large trans cooler if you're putting all the power to a 4L60E.
      I agree, that rpm at 70mph isn't bad. Where I live I usually drive 75-80mph on the highway. Good advice on the trans cooler especially with a looser converter.
      http://www.youtube.com/user/cutlassrkt?feature=mhee
      69 cutlass - 5.3l L33, Jakes stage 3 4L80e, 275/40/17 proxes tq

    5. #5
      Join Date
      Jan 2006
      Posts
      385
      Country Flag: United States
      I vote for the 3.55 as well. With my 3.42 and 700R4 (same gear ratios as the 4L60) I'm doing about 2400 at 70 mph.

      And BTW, if you really want to have some fun with that thing, stick a gear vendors OD behind it. Eight gears... it is SUCH a blast...
      1971 Camaro
      GM HT383, MiniRam EFI, AFR heads
      "8-speed" trans (700R4 + Gear Vendors OD)

    6. #6
      Join Date
      Oct 2004
      Posts
      2,544
      Country Flag: United States
      Only about 100rpm differential cruising in overdrive between the two. But the part throttle tip-in and acceleration will be a noticeable. Go for the 3.73.
      Red Forman: "The Mustang's front end is problematic; get yourself a Firebird."

    7. #7
      Join Date
      May 2015
      Posts
      249
      Country Flag: United States
      Depends on what diameter tire are you going to use. 26" tall? 3.5 , 28" tall 3.73

    8. #8
      Join Date
      Feb 2011
      Posts
      284
      Yup, very true. The deep 3.06:1 first gear of the 700r/4L60 was designed by GM to get cars moving off the line, making them feel peppy even way back when 305's were roaming the earth. A modern car with lots of power, 3:73's and 25" tires will be spin city in first gear. 27-28" tires, not so much.
      70 GTO - Alum 5.3/4L80e, 7875
      17 GT350

    9. #9
      Join Date
      Aug 2010
      Location
      Seattle area
      Posts
      360
      I have had good luck with 3:42 gears .
      ;

    10. #10
      Join Date
      Oct 2013
      Posts
      101
      Country Flag: Canada
      going with 3:55 gears. Doing a cam upgrade and a Coan 2800 stall converter, should have plenty of gear while still having good OD RPM

    11. #11
      Join Date
      Feb 2008
      Location
      Texas
      Posts
      302
      Country Flag: United States
      By the way it's a ratio of 3.55 to 1(3.55:1) not 3 to 55(3:55). The drive shaft turns 3.55 times for every turn of the wheel.

      http://www.youtube.com/user/cutlassrkt?feature=mhee
      69 cutlass - 5.3l L33, Jakes stage 3 4L80e, 275/40/17 proxes tq






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