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Richmond Gear 6900331 Ring and Pinion Set 4.88:1 Ratio GM 8.875 in 12-Bolt

(Chevrolet Camaro 1967-72, Impala 1965-72, Malibu 1965-67, Chevelle 1964-73, Caprice 1966-72, El Camino 1965-73, Monte Carlo 1970-72 + 42 more models)

Part of: Richmond Gear Excel Differential Ring and Pinion Set

Other options in this family: Richmond Gear F9411 Richmond Gear F88410 Richmond Gear 4900391 Richmond Gear 12BC373T Richmond Gear 6903041

Manufacturer

Picture for manufacturer Richmond Gear

Part Number

6900331
7 reviews
Sale Price

$292.16

1 left at this price

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Product Details

The Richmond Gear 6900331 is a high-performance 4.88:1 ratio ring and pinion gear set designed specifically for GM 8.875 inch (12-bolt) passenger car differentials. This matched pair delivers the precision and durability demanded by serious street and racing applications.

Key Specifications:

  • Gear Ratio: 4.88:1 (39 ring gear teeth, 8 pinion teeth)
  • Application: GM 8.875 in. (12-bolt) passenger car differential
  • Ring Gear Diameter: 8.875 inches
  • Pinion Spline Count: 30 splines
  • Pinion Shaft Diameter: 1.625 inches
  • Carrier Series: 4 (requires 3.90:1 or numerically higher carrier)
  • Ring Gear Bolts: 12
  • Standard rotation design

Richmond Street Gear Quality:

  • Computer-controlled manufacturing with precision tolerances to 1/1000th of an inch
  • Each gear set is a matched pair, pre-run on gear test machines for optimal fit
  • Special heat treatment process for enhanced strength and durability
  • Marked with specific backlash and pinion depth settings for precise installation
  • Ground pinion threads for trouble-free installation

Richmond Gear has been the trusted choice of racers for over 80 years, with their Double Diamond logo representing the highest quality gears in the industry. This gear set is sold as a matched pair and requires professional installation with proper setup tools. Note that installation components such as bearings, shims, seals, and crush sleeves are not included and must be purchased separately.

Important Installation Note: This 4.88:1 ratio requires a Series 4 carrier (from factory 3.90:1 or higher applications). If replacing a 2.73-3.90 ratio carrier, you must use a compatible higher ratio carrier.

Products specifications

Fits

Chevrolet Camaro 1967-72, Impala 1965-72, Malibu 1965-67, Chevelle 1964-73, Caprice 1966-72, El Camino 1965-73, Monte Carlo 1970-72, Nova 1964-67, 1969-72, Chevy II 1964-68, Bel Air 1965-70; Pontiac GTO 1965-72, Firebird 1967-72 + 37 more models

Calculator

Gear Ratio Calculator

Carrier Series

4

Cover Bolts

12

Installation Kit Included

No

Notes

3.90:1 or numerically higher carrier.

Pinion Gear Teeth

8

Pinion Shaft Diameter (in)

1.625 in.

Pinion Spline Count

30

Quantity

Sold as a set.

Ring and Pinion Ratio

4.88:1

Ring Gear Bolts

12

Ring Gear Diameter (in)

8.875 in.

Ring Gear Rotation

Standard

Ring Gear Teeth

39

Tool

Transmission Lookup

Ring Gear Bolt Quantity

12

Cover Bolt Quantity

12

Ring Gear Tooth Quantity

39

Differential Carrier Break

3.90 and Higher

Differential Case Design Type

GM 8.875 Car

Pinion Shaft Diameter

1.625

Ring and Pinion Gear Ratio

4.88

Ring Gear Material

8620 Steel

Ring Gear Diameter

8.875

Pinion Gear Tooth Quantity

8

Prop 65

WARNING: Cancer - www.p65warnings.ca.gov

Position

Rear

easy

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Best Price around. Ordered Friday Shipped Monday. Thanks

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