Hi I'm new to this site and was wondering how I can find out if my 82 camaro has a posi or not I've done a burnout and there are two big black marks but when I pull out of a junction and put my foot down only the inside wheel spins whichever way I'm turning

 

You can check for the G80 code on the RPO decal on the bottom of the console lid. This might also be located behind the spare tire cover. If you don't have the G80 code then it should be a standard differential. If you do have the G80 then it is probably an Auburn differetnial. These will wear out eventually and start allowing only one tire to spin. When this happens you either have to replace the Auburn or live with it spinning one tire.