What RPM's are you running at 60mph?

24.8" tire, 3.73, 3050 @ 60 MPH; once the OD actually works: 2200 @ 60 MPH.

64DartGTinAZ said

You can figure yours out here:

http://www.coastdriveline.com/htmlfolder/calculator2.html

Click to expand...

HAH!! My local drive-line shop.