2.73 rear end

How do I know if my 2.73 open is an 8.5 or 7.5 rear end?

Short of dropping the end cover off the diff and measuring it, you could always drop the gas tank and pull the SPID paper off of the top - assuming of course that it's still there. If it is, look for a "G87" code on it, if you see this then you have the 8.5". If you see "G89" instead, you have the 7.5".

go here, for all your rear diff stuff...according to the site i think all 72-79 came stock with a 8.5...assuming your name means you have a 74 nova...they all came stock with a 8.5(with the acception of some 7.5s)...my 73 has a 8.5 if correct....

http://www.novaresource.org/axle.htm

Anybody know if the '74 2.73 is 28 spline or 30 spline? Lookin to put in a 3.73. Thanks

well i guess you can....they are both a 12bolt