3.42 or 3.73

[95slowcar]

Which would be best? I have a 3.4 with auto. trans. Also does anyone know how much the install costs?? thanks for the help..

[Camaro_SLP]

3.42's are the best gears to work with. You can easily reprogram your PCM to correct the speedo, and they won't kill your gas mileage. However, I believe you have 3.23 gears, so you most likely wouldn't feel too much of a difference. I would suggest also purchasing a posi to install with the gears. 3.73's will be faster off the line, but it will hurt your top speed more.

Install varies. Shop around and ask.

[95slowcar]

Is it possible that my car has posi or Limited slip? Or is that only with the Z's?

[Bliggida]

The difference between the two will act simillar to the difference of about 15 horsepower on your particular engine.

Don't worry about top-speed, it WILL NOT be a factor.

So if you have 3.08's now...
3.42's will feel like 17-18 horsepower gained
3.73's will feel like 34 horsepower gained.

[ August 08, 2003: Message edited by: Bliggida ]</p>

[Camaro_SLP]

<blockquote>quote:</font><hr>Originally posted by Bliggida:
Don't worry about top-speed, it WILL NOT be a factor.
<hr></blockquote>


It will be a factor if he doesn't recalibrate his speedo and still has a governor.

Posi came with the Y87 package..check your RPO codes and look for 'Y87'. I doubt you have it though.

[95slowcar]

This probably sounds stupid, but what is a RPO code?

[Bliggida]

Stock goverened at 115 MPH.
With 3.73's and a 26.18" Wheel diameter means he'll run about 18% slower from his previous top speed - around 93 MPH. That is assuming he does not change or recalibrate his speedometer - which SHOULD be an integral part of swapping gears. In which case he would continue to achieve 115 MPH as he did stock.

Without the Govenor, 3.73's have the possibility of 158 MPH. He ain't gonna pull that!

[Bliggida]

<blockquote>quote:</font><hr>Originally posted by 95slowcar:
This probably sounds stupid, but what is a RPO code?<hr></blockquote>
No not stupid. Very relavent

Regular Production Order
means it was a factory option you had available to you. Should be series of codes on a sticker in your glovebox. It told the guys on the line what to put into your car - how it was to be built.

[Camaro_SLP]

RPO codes= Regular Production Order Codes.

They are a list of letters/numbers located on the door jam or in the glove compartment that let you know of the options on your car.

http://tech.firebirdv6.com/RPOcodes.html

There is a list of all of them.

GU4 AXLE REAR, 3.08 RATIO

GU5 AXLE REAR, 3.23 RATIO

GU6 AXLE REAR, 3.42 RATIO

Look for either GU4, GU5, GU6 and that will let you know what gears you have. All the codes are only 3 characters long.

[Devilboy28]

The 3.73s rock, but your top end is a few mph slower. Unless you are racing I wouldn't worry about not being able to do a sustained 118mph. I top out around 94-100mph.

[95slowcar]

Thanks. I'm going to run out and check the RPO codes and see what it says.

[95slowcar]

Nope, no Y87 :( . Had the GU5 so I guess I ahve 3.23. Ok, thanks for the help ya'll. [img]smile.gif[/img]

[Bliggida]

<blockquote>quote:</font><hr>Originally posted by 95slowcar:
Nope, no Y87 :( . Had the GU5 so I guess I ahve 3.23. Ok, thanks for the help ya'll. [img]smile.gif[/img] <hr></blockquote>
Auto's weren't originally equipped with 3.23's were they? It was my understanding that3.23's were a V6 T-5 gearing only.

[Camaro_SLP]

<blockquote>quote:</font><hr>Originally posted by Bliggida:

Auto's weren't originally equipped with 3.23's were they? <hr></blockquote>

I have an auto that originally came with 3.23's.

[Bliggida]

Interesting...and rare. Its not listed as an option for automatic cars (based on the 1998 Camaro Technical Data released by GM)