nice truck to start with, i've seen worse, like my parts truck! about the rearend you can take the cover off and theres 2 numbers stamped on the ring gear. ##-##. This is the number of teeth on each gear. Divide the two numbers and this will give you the gear ratio! to tell if you have a posi or not when you have the cover off, if you see springs and plates in it then its a posi, but if you only see gears and it looks all open, then you have a non-posi! this is what a posi looks like!
http://www.gtoforum.com/attachments/...ctory-posi.jpg