the rear has 50k miles on it, person says its in good condition off a z28 asking 250, what is it really worth? seeing that i wont be able to test it until putting it on the car. also whats a use slp loudmouth one catback worth?

 

$250 isn't bad. You can probably get it down to $225 or $200 since it's only a 2.73 rear. I'd double check to make sure that it's from a Z and not V6. Don't want no open diff. The catback I'd say $300 if it's still in good shape...not sure what they go for new though.

 

spin one of the axles and check the other one if it spins the same way its a lsd if it spins opposite than its open

 

Depends on how used the catback is. They are around $400 new, so for a used one in good condition, maybe $100-$150

 

ill offer 150 see if he bites, as for the rear, when the wheels go in the opposite direction its limited slip?

 

Opposite direction means open rear end. Wheels spinning same direction is limited slip or "posi."

 

hmm, the reason i ask is that on my car when i spin one wheel the other goes in the opposite direction, but on the original window sticker it has the limited slip option. and when i burn out, both wheels burn

 

Does it only list the LSD option? Or does it have like a check mark or something next to it? If you're spinning them and their spinning opposite, there's no doubt it's a open diff. As for the burn out, a open diff can leave two black marks.

 

Honestly then im not sure. My truck had a G80 locking diff but would still only do a one wheel burnout...