I am somewhat of a newbie to chevy axles and such, so bear with me. I did a search, but didn't come up with what i am looking for.

I need the size of a 12 bolt ring gear. 9.5? 10.5? i am looking to find a full spool for a 12 bolt going inder my 4 runner. thanks.

8 7/8"

the 9.5 and 10.5 you are thinking of are the semi- and full floating 14 bolts, respectively.