I am thinking of changing gears to get a little quicker et. What would be the best choice for a car that is an auto and driven on the street all the time? What kind of price range am I looking at for a shop to do this and possibly add a posi unit?



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1984 Camaro Z28

Crate 350
Edelbrock Intake
Edelbrock TES Headers
Hooker 3" Catback
ASP Underdrive Pullies
Corvette Shift Servo

JBL 150watt Amp
JL Audio 12" sub

 

I would suggest 3.42's if you drive it every day.They give ya good out of the hole peformance and good drivability and mileage.The gears will cost ya around $200.00 and the install kit will cost around $100.00.Shops around here charge $200-$250 to set up the gears.I posi unit will be around $400.00 but you can get the take off posi's alot cheaper.Another option would be to check around the junk yards to find a 3.42 rearend.Around here ya can find them pretty easy and cheap,around $200-$250.If its not a posi get a powertrax for $315.00 and put it in.

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Superman
Rev'n to Seven

 

I've got 3.73s in the rear of my car. They're great. I really don't think you could go wrong with a 3.42 or 3.73, either one would be good for a street/strip setup. You'll get higher cruise RPM with the 3.73s, but I think the quicker acceleration is worth it. Definately get the posi unit too, with the steeper gears and the peg-leg differential you'll smoke the passenger side tire to oblivion.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

i have a peg leg rear, and am dying to get 3.42's(current ratio is either 3.73 or 4.11, i didnt install it, the guy before me got it out of the 'yard, and wasnt sure what ratio it is)anyways, is powertrax a company? is it posi? or better just used for the strip? i have a 10bolt rear, and my soon to come engine will have right at 450ft/lbs of torque.. will it handle it?

 

The powertrax is excellent street/strip unit. It will handle the power, but the rest of the rear end may not.


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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

Put your car in drive, not overdrive, and get on the freeway at 70 MPH. Look at what RPMs you're at. Tell us the result and that'll be what gears you have now. For example, with my 3.45 rear end (swapped in a 9-bolt) I'm around 3450 RPMs at 70 MPH.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

What kind of et improvement would I see with the new gears and a posi?


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1984 Camaro Z28

Crate 350
Edelbrock Intake
Edelbrock TES Headers
Hooker 3" Catback
ASP Underdrive Pullies
Corvette Shift Servo

JBL 150watt Amp
JL Audio 12" sub

 

or you can just jack up the back wheels and twist the drive shaft.
how ever many revolutions of the drive shaft it takes to turn BOTH wheels over once (wheels must turn in same direction) is your ratio.

you can do this and count # of revs in your drive shaft for 10 revs of your wheels and then divide by ten also if you want to be really accurate.

I say you might want to do it this way because if the gears arent origonal then the speedo will be off because if you change the ratio in the back you have to change the speedo gear in the tranny to correct the speed reading.


[This message has been edited by 88305tpiT/A (edited November 28, 2000).]

 

Very good point, 88.

 

I have a Powertrax unit in my 12 bolt, and it stands up to 450 H.P. pretty good so far. The Powertrax unit is actually better than a posi in a couple of ways. For one, you can install it in your own driveway in a couple of hours because you don't have to remove the carrier or have your rearend set up again. The other thing is that a posi is referred to as a "limited slip" because it uses clutch discs and springs to control wheel to wheel traction. The Powertrax unit is like having a racing spool with the ability to still differentiate on turns. It gives you solid axle traction when you're going in a straight line. I guess you could say it's a "true locker" type design. The only drawback I've noticed with the Powertrax is that it's a bit noisy around turns when it's "indexing", or ratcheting. They give you two sets of springs with them. I used the heavier street/strip springs in mine. They might be a little quieter with the street springs, but I chose the quicker and stronger lockup of the heavier springs for mine.If you don't mind the little bit of extra noise though, the Powertrax units give you incredible traction. You can buy them through Summit or Jeg's mail order.

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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

[This message has been edited by Pat Hall (edited November 29, 2000).]