Precision Gear - GM 8 1/2" Ring and Pinion Gear Sets

Ring Gear Diameter:
Pinion Shaft Diameter:
Ring Gear Bolts:
Left Hand Threads:
Pinion Splines:
Cover Bolts:

8 1/2"
1.625"
10
7/16" x 20
30
10

Model	Year
K10, K15 •	77-87
K10, K15 •	82-Pres.
K20, K25 •	77-87
C10, C15	78-Pres.
G10, G15	79-Pres.
G20, G25	79-Pres.
Buick Full Size	77-96
Blazer •	77-91
Apollo	73-77
Regal	73-77
Century	73-77
Biscayne	71-74
Grand National	84-87
Skylark, GS	71-75
Skylark, GS	77-79
Chevy Full Size Car	71-96
Chevy II	71-79
Nova	71-79
Camaro	71-81
Firebird TA	71-81
Cutlass	71-77
El Camino	71-77
Monte Carlo	71-77
Electra	76-78
Gran Sport	73-77
Impala	91-96
LeSabre	73-74
Olds Full Size	71-89
Pontiac Full Size	71-89
Hurst Olds	85-89
Omega	73-75
Omega	77-79
Grand Prix	71-77
Lemans	71-77
GTO	71-77
Roadmaster	71-74
Roadmaster	91-96
Ventura	71-77
Phoenix	71-77

Ratio	Teeth	Part #
2.73	49-18	GM10/273
3.08	40-13	GM10/308
3.42	41-12	GM10/342
3.73	41-11	GM10/373
3.90	39-10	GM10/390
4.10	41-10	GM10/410
4.56	41-9	GM10/456
4.88	39-8	GM10/488
5.13	41-8	GM10/513 *

Installation Kits	Part #
Master Installation Kts
Front (Truck)	GM10/MOKITF
Rear 99 & Up	GM10/MOKITRL
Rear	GM10/MOKITR
Installation Kits
Front (Truck)	GM10/KITF
Rear	GM10/KITF
Mini Installation Kits
Front (Truck)	GM10/MKITF
Rear	GM10/MKITR
Pinion Bearing Set-Up Kit
	PINSU1

* Requires a modified cross shaft for installation. Use Part Number GM10/XSM.

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

• Front w/o IFS 
• Rear
• K Series

Tech Note:

When replacing 2.56 and numerically lower ratio gear sets with a 2.73 or higher gear, the case must be changed to a 2.73 and higher case.

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