does an 88 4cyl have a posi rearend??

Chances are slim...

Chances are slim, since there isn't that much breaking traction with the 2.3. The easiest way to tell is to look at the tag on the axle, or check the door tag. The axle tag will read "3L45" if it's posi "3 45" if it's open. The numbers of course are the gear ratio.