boola1341

iTrader: (1)

i have the 02 z28 camaro a4. What is the stock gear ratio? I can do 70mph at 2000 rpm. i'm planning on installing 3.73 gears. Will i have to change the differential and what rpm will i be at doing highway speed (60-65mph)

slowjoe99

iTrader: (7)

i think 2.73 or 3.23? i have 3.23's and I'm doing about 21 or 22 hundred at 70mph i think. just jack up the back of your car get under it and make a mark on the drive shaft and a mark on one of the tires and spin the wheels in the same direction at the same time and speed and count how many times the drive shaft turns before the wheels made 1 complete revolution. remember to put your car in neutral and make sure it's not on any kind of a hill cause the front tires will roll freely...

RPM WS6

iTrader: (3)

You have either 3.23s or 2.73s. Check your RPO codes for either GU5 (3.23) or GU2 (2.73).

LS1 Freak

iTrader: (7)

Well, on my 01 SS I have 3:23's if that will help you!!!

N2OGTO

check rpo's in door

LiT1_up

iTrader: (16)

on stock size tires with 3:73s i'm turin 2500 rpm at 75 mph.

Splitz

iTrader: (1)

My 02Z has stock gears @ 2.73 (GU2). Before cam, was cruising 70 MPH at justa bout 2000 RPM's.

waldershrek

iTrader: (1)

I have 3.23's in mine

BOOSTEDXTACY

I know this is a very old thread and my appolgies ahead of time. I am new to this site and just picked up a 2002 Z28 and am trying to figure out what my gearing is and am not sure what these rpo codes are? Any help would be great. Thank you again.

LS-ONE_DAY

Open the drivers door. There will be a rather large sticker with a bunch of letter/number combinations, should be organized alphabetically IIRC. Look for GU5 (which would be 3.23) or GU2 (which would be 2.73). You didn't specify automatic or manual transmission. Those assume automatic. If you have a manual you have 3.42 gears.

Those are all the ratios offered from the factory

For reference: