GM 8 7/8" Car
 
Ring Gear Diameter:
Pinion Shaft Diameter:
Ring Gear Bolts:
Right Hand Threads:
Pinion Splines:
Cover Bolts:
 
8 7/8"
1.625"
12
3/8" x 24
30
12
Model
Year
Chevelle 64-72
Camaro 67-72
Chevy II 65-72
Nova 65-72
El Camino 65-72
F85 68-70
Firebird 67-72
Grand Prix 70-72
GTO 65-72
Impala 65-72
Le Mans 65-72
Monte Carlo 70-72
Ratio
Teeth
Part #
3.08
40-13
GM12/308C
3.42
41-12
GM12/342C
3.73-
41-11
GM12/373C-
3.73
41-11
GM12/373C
3.90+
39-10
GM12/390C+
3.91
43-11
GM12/391C
3.91+ 43-11
GM12/391C+
4.10 41-10
GM12/410C
4.10+ 41-10
GM12/410C+
4.30 43-10
GM12/430C
4.56 41-9
GM12/456C
4.56 41-9
GM12/456P
4.56+ 41-9
GM12/456C+
4.88 39-8
GM12/488C
4.88 39-8
GM12/488P
5.14 36-7
GM12/514C
5.14 36-7
GM12/514P
5.38 43-8
GM12/538P
5.57 39-7
GM12/557P
6.00 36-6
GM12/600P
.................................................

– Gear set fits 3.90 or higher case.

.................................................

+ Gear sets are designed "extra thick" to be
used with 3.07 to 3.73 case.

.................................................
Requires a modified cross shaft for installation. Use part number GM7/XSM.
.................................................
Installation Kits
Part #
Master Installation Kts
GM12/MOKITC
Installation Kits
GM12/KITC
Mini Installation Kits
  GM12/MKITC
Pinion Bearing Set-Up Kit
  PINSU5
Pro Gear statement 
  click here
 
 
       
AMC Ring & Pinion Sets
Chrysler Ring and Pinion Gear Sets
Dana Ring and Pinion Gear Sets
Ford Ring and Pinion Gear Sets
Suzuki Ring and Pinion Gear Sets
Toyota Ring and Pinion Gear Set
Ultralite Ring and Pinion Gear Sets
Precision Gear Differentials
Precison Gear Installation Kits
Precision Gear Bearing Set-Up Kits
Precision Gear Ultralite Series
The Precision Gear Story
Precision Gear Tech Help
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• GM 7 1/4"GM 7 1/2" 
  (GM 7 5/8")GM 7 3/4"
  Borg-WarnerGM 8.2" ChevyGM 8 1/4" IFSGM 8 1/2"GM 8 7/8" CarGM 8 7/8" TruckGM 9 1/4"GM 9 1/2"GM 10 1/2"GM 11 1/2"
 
Tech Note:
When replacing 3.73 and numerically lower ratio gear sets with a 3.90 or higher gear, an extra thick gear must be used or the case must be changed to a 3.90 and higher case.