10 bolt rebuild

[softballnrd27]

I want to add some gears to my rear to make it run a little better, I'm pretty sure it has 3.08s in it but not 100% sure. While I'm in there I'm going to throw a posi in it. I know they aren't the best for power but i'm not going to throw sticky tires on it and run it down the strip. I want to order the parts before I tear into it. I have an 85 GMC and I just want to make sure i get the right parts. Were they all 8.5" and 28 spline axles? If I get 3.73s do I get the 2.73 and up carrier? Would 3.73s be good for a 5.3 243 heads small cam and th350? I will build a real rear end later on but I can't drop $3k on a new rear.