I am new to this forum and I am about to pull the trigger on a 69 Camaro with a 10 bold posi I believe it is 3.31 gear. What is that worth if I were to sell and where on here can I possibly find a 12 bolt that would fit my new Camaro? Also how much can I expect to spend on the 12 bolt and what could I sell the 10 bolt for? Thanks Everyone!!!

 

Welcome here
I went through the same process on my 68 with a 10 bolts 8.2" 1:3.08
Considered getting a Moser 12 bolts but did not wanted to spend that much.
Then I found some much cheaper complete rear ends from Quick Performance.
Then I thought I would stay with original parts. So current option is to go with a Limited Sleep Differential (LSD) as the original differential needed a rebuild and it's not much more expensive to go on LSD.
This way I will have a more sturdy solid rear end for about 500-600$, with original parts for an original looking car.

 

Why do you want to swap in a 12 bolt,planning on big HP and a lot of hard launches?
Is the car a stick or automatic? In a stock car especially with an auto that 10 bolt should be just fine.
I'd expect the 10 bolt posi in decent shape should bring about $500 but it depends a lot on where you are and who's looking for one.
Finding an original 12 bolt may be hard to do especially one that doesn't need a rebuild but you might get lucky on craigslist or facebook marketplace etc.
1968-1972 Novas are the same so keep that in mind looking for used parts.
If you're ready to spend big for a high horse build here you go,note the options list and do the math.
https://www.moserengineering.com/12-...d-package.item

 

If it ain't broke, don't fix it.

 

if its an all original car no matter what you do keep the rear end for future value. dont know if the rear unit is tagged or identified by numbers to show it belongs to this car you may want to take photos and mark it when you remove to have at least some documentation.

 

I don't think the rear axle has any reference to the car's VIN, but it should have build dates to match the cars build date and castings numbers to match what was offered during the production run. Pretty sure the axle casting also should have a casting date too. I believe the production date and axle ratio markings are on the right axle tube if I remember correctly.

 

OP

You don't need a 12 bolt unless you intend to drag the car and making over 450 REAR wheel HP...and then only if you do 5k rpm clutch dumps

The Eaton LS diff is a very good upgrade to a 8.2 10 bolt if its not a posi diff

 

Another option is an 8.5 10 bolt from a 1973-4 Nova .Its a bolt in .and will handle a decent amount of HP .I have an 8.5 10 bolt in my 1979 Z-28 with a Super T-10 4 speed and a 500 HP supercharged small block chevy.