Howdy: I have a 10 bolt ring and pinion setting around I believe it to be a 10 bolt. How do I measure the ring size 8.2 or 8.5 I did count the spline and it has 27 which should be BOP. Thanks, haven't been here in years, but I didn't forget you guys!

The answer's in your question.
How do I measure the ring size 8.2 or 8.5
8.2 or 8.5 are the ring gear diameters.

http://www.richmondgear.com/01gm.html
Click on a size for diameter,pinion diameter ,spline count,etc.