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  • Gear Ratio

    Happy thanksgiving all.
    What gears would be the best for a 1/4th mile pick up truck out of the 3.42 gears or the 3.73 gears? i have the 3.42 ones just wondering if it would be better if i put 3.73 gears in it instead? because i like my gears alot right now and have been beating other trucks thats have the 3.73 gears? whats the differences betwenn the two?

    Thanks, Phillip
    1997 Chevy Silverado 1500 2wd
    - 5.7( 3.42 gears)
    Dyno test results soon..

  • #2
    Re: Gear Ratio

    When you are in OD you want to add the difference in gear to your RPM. For example if you went from a 3.08 to a 3.73 your cruising RPMs would change about 600 or so RPMs. I wouldn't go from a 3.42 to a 3.73. I son't think they is enough gain to be there to make the swap worth it. Unless you are going to add a posi at the same time and needed new gears then I would. I did go from an open unit and 3.08s in a Blazer to 3.73 and an Auburn posi unit. I dropped almost one full second. There is alot to be said about rear end mods. Think about going 4.11
    Thank you to those who serve in our military defending our freedom

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    • #3
      Re: Gear Ratio

      Go with 4:10's!! Likewise 3:42's and 3:73's aint that much of a difference.

      96'RCSSB 5.0L Cammed LS1 or 6.0 Coming Later
      03'RCSSB 5.3,3:73's,G80 SOLD!!

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      • #4
        Re: Gear Ratio

        what kind of difference am i looking at with the 4:11 gears- compaired to what i have now??
        1997 Chevy Silverado 1500 2wd
        - 5.7( 3.42 gears)
        Dyno test results soon..

        Comment


        • #5
          Re: Gear Ratio

          Add about 600 rpms to your cruising speed is what will be affected the most. Take a 4.11 and a 3.42 and subtract the two and that will give you a good idea of what to expect.
          Thank you to those who serve in our military defending our freedom

          Comment


          • #6
            Re: Gear Ratio

            yeah but power wise...... will i see a huge increase in speed and power?
            1997 Chevy Silverado 1500 2wd
            - 5.7( 3.42 gears)
            Dyno test results soon..

            Comment


            • #7
              Re: Gear Ratio

              You wont gain any power or gain or lose speed at all with a gear change, but your truck will have a greater mechanical leverage than with the higher 3.42 gear.

              You will notice higher revs at the same speed on the highway, and acceleration will be more brisk.

              I went from 3.08's to 4.10's and surely noticed a difference but it wasnt a crazy big different. I dropped about 2-3 tenths in the 1/4 mile, and also lost about 2 or 3 mph.
              60ft times dropped by about3-4 tenths.

              City driving is much better, and hills on the highway are a breeze, no TCC unlock or downshift like with the 3.08's. Overall thee truck FEELS lighter and much less throttle angle is needed to accelerate while driving.

              With the 3.08's I would trap in 2nd gear at 5500 rpm.
              With teh 4.10's I trap at 4800-4900 rpm in 3rd gear.

              The fastest I have had my truck was 122 mph which was 4200 rpm in OD with 4.10 gears and a 28" rear tire. I had lots left but the tires I had installed werent in any shape for a top speed run, so I let off.

              For drag racing or street driving for that matter I wouldnt go 3.42 to 3.73 unless you broke the 3.73's or got them for free. If I were you I would go directly to 4.10's as they are ideal for the 1/4 mile. 4.10's were a little low for my 28" tires on the freeway however, 2500 rpm only gave me72 mph, 2250 gave me 65mph. I liek to crusie at abot 75 mph and the revs would be around 2600 rpm, tahts just a tad high for my liking. The same 2600 rpm with 3.73's would give me 83 mph, or 2350 rpm for 75 mph with 3.73's and a 28" tall tire.

              Its all a matter of preference and exactly how you will drive the truck.
              If its primarily drag use, then for sure go 4.10's, and Richmond gears are teh best IMO. I have broken several GM geads and only 1 set of Richmonds. Teh Richmonds finally broke after 4 seperate incidents. the Richmonmd ring and pinion gears digested 1 set of spider gears and 3 Powertrax Lockrite lockers. i simply ground down teh rough edges, reinstalled them and got another 100,000kms of driving out of them. I broke them doing a TC stall test in teh driveway. Best gears I have used.

              Here is a nice reargear/tire height calculator that I use all the time.
              http://www.angelfire.com/fl/procrastination/rear.html
              peace
              Pauly
              Last edited by Pauly; 11-24-2006, 12:33 PM.
              97 GMC 2wd RCSB 5.7, s10 2700 footstall, Hooker 24621hkr LT's , 2.5" cats dual 4"pipes exit B4 pass. side tire, custom driveshaft 3.42 G80 FIPK MAF descreen GM/Mercruiser Marine intake manifold 29lb LS2(EV6) injectors Ed Wright PCM(best mod), LT4 KM 14.8@94mph 2.007 4000lbs 122mph

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              • #8
                Re: Gear Ratio

                Take tire height into consideration, and where your particular vehicle makes peak power. I am staying with 3.42's, I run a 27" tire and have a basically stock L05 w/ bolt ons. My Z28 however, I run a 28" tall tire with 4.10 gears, I'm actually considering going up to 4.30's in the future.

                The major difference, my L05 is out of breath around 4100-4200, and my Z28 pulls all the way to 7100-7200. If I decide to spray again, I'll have to drop gear in the car.
                2000 Z28 - mods?! Previous best - 11.504 @ 122.43 MPH, weak 1.852 60'
                1991 Z28 - 99% stock daily driver.


                I wish my lawn was emo so it would cut itself.

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                • #9
                  Re: Gear Ratio

                  alrighty, thanks guys... i think im going to keep the gears i have now. Prob in the near future ill get PCM tuned but Ed Wright, after i get some borla headers. well see how it goes.
                  1997 Chevy Silverado 1500 2wd
                  - 5.7( 3.42 gears)
                  Dyno test results soon..

                  Comment


                  • #10
                    Re: Gear Ratio

                    I would get eitehr 3.90's which I had in my 97 before I sold it or 4.10's IMO
                    06 Crewcab 2wd 5.3 Wheatley tune using HPTuners,4.10,comp cam,Yank,longtubes,Heads and much more
                    TXvortec350 AKA Wheatley

                    03 Tahoe 5.3 Wheatley tune using HPTuners

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