Chevy 12 bolt 3.90 ratio gear set for GM 8.5/8.625 ring gear
Richmond Gear part # 49-0034-1
1.626 dia pinion, 30 spline pinion. Pinion is 10 teeth and ring gear is 39 teeth.
Background: Several years ago I had one of the large K5 Blazer Chevy trucks and bought my first enclosed trailer. The OEM 3.08 gear made it gutless! I tried this 3.90 gear set for a few weeks. It improved it but then I ordered a new Dually truck. I reinstalled the OEM gear set and sold the Blazer. I still have this gear set sitting on my shelf in the original box in perfect condition. This is the Richmond 8620 alloy street gear that works well on the street or strip and is much stronger than the OEM gears. Also, these gear sets were made in the USA!
This gear set is $227.99 online. Buy this set for half price, $100.