I thought this rear axle ratio was only for the V6 models. I just found out that is the ratio in my 2002 Z28.

 

Stock with the Auto tanny. Check your shift plate and If no 1st gear markings then it sure is a 2:73 rear.

 

what is the stock rearend in an M6. How do i tell which i have?

 

M6 cars came with 3.42's, look for RPO code GU6 on the driver's side door. Welcome to the board.

 

Three Factory 10-bolts for v-8's:
1) 2:73 Auto Standard
2) 3:23 Auto Optional
3) 3:42 Manual 6sp Standard

 

And Ford nine inches for those who cant keep a 10 bolt from grenading lol.

 

So I am pretty much stuck with the worst rear axle in a V8. So If I beef up the LS1 with bolt-ons Im going to have trouble putting it to the ground?

 

There's nothing wrong with 2.73's. I've now got 4.10's with the A4 in my '02, and yet there's a part of me that wants the 2.73's back for everyday driving.

On the highway the 2.73's ruled.....upto ~80 mph, you punch it and the tranny kicks right down into 2nd gear, and pulls to ~100 mph, then 3rd takes the car all the way up to ~160 mph! ALSO, at a slow roll upto ~40 mph, it'll kick into 1st gear and go all squirrelly! With 4.10's, 1st gear is over with quick, and you never see it again. Beyond that, no matter what, the tranny will only ever drop 1 gear at a time, unless I manually downshift. Besides running a little better 1/4 mile, they're not what I thought they would be:blah:.

BTW:
GU2 = 2.73's
GU5 = 3.23's
GU6 = 3.42's (already mentioned above, and only for 6-speeds).

 

you can't go by this. i had 2.73s originally and i have a 1st gear position and marking. this rule only applies to the LT1 years as far as i know.

 

I believe I have my 3:42 set if you are interested. I'm in Moreno Valley, so you could pick them up if you want. They were on my M6 car. Not sure what the going rate is, make me an offer if you want...