Hello all, need your expertise again, i know on the differential on a 1980 dana rear end there are casting numbers. what do they mean as far as what ratio you currently have and want to be 100% positive. i am familiar with the physical way to test for it but i would like to rebuild the case + change out my ring gear and pinion set for more take off !!

The casting # tells you nothing other than the casting #!
The ratio/date code will be stamped in the bottom part of the diff itself. Fortunately, you don't even have to look. All '80 cars had 3.07 ratios.


Check out the following link. It gives more info on coding. If you have the aluminuminum diff, some of the photos may not help, but the pertinent info(Ratio/date codes) will be in the same location.

                                                         CLICK on image for linkAdams' Apple2007-04-15 07:52:01

thanks alot for the quick reply !! i had been kickin' round the net and seen lower ratio's associated with the early 80's and thought mine was one of those lucky 2.72 boys  !!  i am planning on an upgrade to get some go-go off the line.