ring gear 7.50 what does this mean?

[gutlesscutlass]

my rpo code is g89

 

[85 Cutlass Brougham]

The ring gear diameter is 7.5 inches. It means you have the sucky axle that 98.5% of all G bodies have. It is also the rear axle that is most common on 3rd gen F bodies (Aussie B-W 9 bolt 7.75 excluded), all 4th gen F bodies, some B bodies and most S trucks that were 2wd (some 4x4's had the 8.5 in later years). It is also found in it's original application: The Chevy Monza and it's clones.