Rear-end

[slim]

Can anyone tell me how to tell the case number, spline etc. of a rear-end most of the markings are gon (painted stuff) but can read the numbers   Sorry i'm pretty new to all this

[slim]

also year, how to tell what size (ie. 8 3/4 or 9) and any other info

its currently in my 66 dodge charger but i dont know if it the original

[Ghoste]

If it's the original one it is likely and 8 3/4 and probably a 742 or 741 case.  If it has an access cover on the back of the housing, it is not an 8.75.  If you remove the bolts on the front and the entire differential unit is removed from the housing in that fashion, you have an 8.75.  Look on the side of the diff unit and you should see a group of numerals that are cast into it.  The last three digits will tell you what case you have.