i have a 85 posi rear and a 95 camaro rear what problem would i run into swapping gears

 

Just the ring and pinion, no problems since they're interchangable. If you want to use the carrier from the 95 (posi), you're going to need 28 spline axles for a third gen housing. If you wish to keep your 85 posi then just swap the gears.

 

so to make it clear my 85 gears will slide right in right.

 

The gears are interchangeable as long as they are the same series (2 or 3). If they are both 3.23 or numerically higher gears then they are 3 series gears and are interchangeable. If they are 3.08 and numerically lower gears then they are 2 series gears and are interchangable. If one of them is a 3 series gear and you want to use it on the posi that is a 2 series carrier this can be done using a ring gear spacer. If you want to run the 2 series gear on the 3 series carrier, this is not possible and you are out of luck.