Do you think that my 1992 camaro rs 305 tbi 25th Edition came with limted slip?

 

Yes. But check the RPOs, or pull the cover to be sure.

 

No, unless someone put one in.
They come stock with 10 bolt, 2.73 open rear ends.

 

Powerbrake and see if you can get both wheels to spin.

 

The rpo code for a posi on a 3rd gen is G80 followed by letters and a number, like this which tells the gears:
GS4 3.70
GT4 3.73
GT5 4.10
GT7 3.33
GT8 4.10
GU1 2.41
GU2 2.73
GU4 3.08
GU5 3.23
GU6 3.42
GV2 5.83
GV4 3.36
GV8 2.72
GW4 3.31
GW6 3.27
GW9 2.93

 

You can get an open rear to lock eventually after spinning long enough

 

How long does it take? On many cars we powerbraked for 10-20 seconds and the pass side wheel was the only one spinning.

I also found out that jacking up the rear of the car and turning one of the back tires to see if the other one spins the same way or opposite does not mean you have or don't have posi.
Both of my 3rd gen rears spun the same way and had posi, but the 4th gen rear I have in the formula spins opposite, just like an open rear but mine roasts both tires. I think my 4th gen has the Zexel/Torsen posi unit.

 

to cheak the rpo where would i look at? the rear end?

 

Screw the RPO. Forget the "2 tires" crap. Don't bother with turning one tire and which way the other one goes.

Take off the cover and look. It's the only way to be sure.

Have you changed the fluid lately? Then it's overdue. You have to take the cover off to do that right anyway. While you're catching up on the maintenance slack-off, make a point of looking at what's inside it.

That having been said, if I was the betting kind, I might be willing to bet money your car didn't come with posi. That doesn't mean it doesn't have it now; but those bottom-of-the-line cars almost never came with that option.

 

With the cover off, what do you look for?

 

a clutch pack....

 

An open rear will have a cross pin, 2 side gears, and 2 spider gears inside its carrier; nothing else.

If you see anything else; preload springs, governor weights, more gears, clutch plates, or any other parts; it might be a posi.

 

Heres a pic of the thingy:

 

This is an open rear just for reference