Rod, In deciding which ratio gearing you have you could check in a Chilton's manual. The manual contains a section listing all the gear ratios for a particular drivetrain combination. Various optioned ratios are also listed for the State of California. It also lists the ratios for coded rear ends. Check at or near your rear axlehousing. Once you find the code/part number you will be able to cross reference it in the same manual. Good luck in your search - I still have to figure out my ratio... Bruce