Want to install posi on 8.2" 10 bolt

I bought a 69 Camaro recently. The problem is that the guy I bought it from replaced out a 4.11 posi rear end with a 308 open differential to up the mileage. He did increase the mileage, and I am happy about that but there is no posi-unit installed.

Of course, I'd love to put in a 12 bolt, but $$ preclude me from doing this. I did a bit of reading online, and will keep the 10 bolt 8.2" that I have. In fact, I think that I will keep the 308 gears ratio to, since this helps on gas. But, I really would like to install a pos-unit.

Here is the question: Not knowing anything at all about trans-axcels, can a posi-unit be integrated with the existing parts, or when installing a posi-unit, are there other componants/parts that have to be changed our as well?

Also, what should I expect to pay to have someone to do the job? Any recommendation on what brands I should consider?

The car has a 454 (545 hp) and a TH350

Thanks for any advice or thoughts

I see units likeTHIS ONE for an 8 1/2" 10 bolt, nothing for a 8.2" This option still costs a lot of $$$

I kept looking around and talked with a couple of people online, and I am now thinking that the best and most economical way to go is with a locker. Powertrax seems to have the best deal going for a locker unit that is reported to be fairly quiet and provides a 100% locking differential, except when turning. The using goes for about 400 bucks, and from all accounts, is a pretty easy garage installation. Does anyone have anything bad to say about this product?