RICHMOND is the leading manufacturer of professional quality, hi-performance ring and pinion sets. For over 80 years, the Double Diamond has signified the highest quality gears in the racing industry! GM 12-BoltInstallation Notes: When replacing a 2. 73-3. 90 ratio with a Richmond Hi-Performance Ring & Pinion, the carrier must be replaced with a carrier from a stock 4. 10, 4. 56 or 4. 88 ratio. When installing 5. 14 to 6. 14 ring & pinion sets, differential cross shaft #RIC80-0269-1 must be used.Pit Stop USA offers Richmond Ring & Pinion Set - 4.88 Ratio, 39-8 Teeth, GM 12 Bolt 69-0033-1 at low everyday prices. Be sure to check out all of our products from Richmond Gear including Richmond Gear GM 8.875" 12 Bolt Ring and Pinion.