79 Malibu rear end help

Over the years i have learned more and more about all different car topics, but one thing i never learned much about is rear ends. I have a 1979 malibu classic, in not sure what rear end it has in it, i just put in a new motor(350) and im just wondering the specifications on the rear end of the car, how much can it handle. The car came stock with a th-350. Also if i wanted to go about making it posi, what would id do to change it up and what would be the best thing to do. Do i have to just change up whats in the housing or the entire thing? Thanks  

If the rear is original it should be a 7.5" 10 bolt with 2.73 gears.  
Horsepower sells Engines and torque wins races.

yeah and thats not good if your 350 has any power at all. thoes 7.5s are junk  

You could install one of many aftermarket kits in your rear end or better yet find another to replace it.  What kind of power are you making, and how do you drive it?  

The 7.5 has slight oval shaped rear cover and the 8.5 has a round cover. Yes those 7.5 are junk but can be made to work with good parts. After all GM used them in Camaro/Firebirds until 2002 with LS1's making 350 hp.  

Ya a lot of people say they are junk but I have been using one in a regal with a Pontiac engine that produces 460 FT lbs of torque and never had a problem the only time I have seen them fail is when they are not setup right.
The 1977-81 7.5 rear are stronger than the 1982-UP rears.  
Horsepower sells Engines and torque wins races.

duplicated and added below... sorry  

We have run around 400HP through these little 7.5's and run mid to low 12's for a couple years, and used as a daily driver, with no probs at all..  I did set up the rear end, and I think I put new guts in it, but I can't remember for sure.. Long time ago.. Now, given a choice I'd use a 12 bolt, or a 10 inch, but rebuilding any rear end is a great education, and you have to do it right.. If you don't, you pay...
This was behind a Saginaw 4 speed in a 65 Elky.. both the trans and the rear end were considered junk by many, but they served me very well...  Oh how I wish I still had that Elky.  

NP Hill.