I have a 1985 iroc TPI. I'm wondering if it has posi traction. Was that available?

do a burn out and see if both tires spin or just lift the diff and spin a tire the other should spin the same way if its posi..........

I think that there is a tag on the front passenger side of the rear axle. If there is, there should be a code on it. You should have no problem finding out this code on the internet. It should tell you if it is posi and the gear ratio of the axle.