GM PRODUCTION OPTIONS RPO FY LY USE DIV MODEL DIVISIONAL RPO DESCRIPTION GM7 82 83 AXLE REAR 2 39 RATIO GM8 76 91 AXLE REAR 2 56 RATIO GO1 85 92 AXLE REAR STANDARD RATIO MERCHANDISING OPTION GS4 85 86 AXLE REAR 2 70 RATIO GT4 76 93 AXLE REAR 3 73 RATIO GT5 76 93 AXLE REAR 4 1O RATIO GT7 89 91 AXLE REAR 3 33 RATIO GTB 76 89 AXLE HEAVY DUTY REAR 4 10 RATIO GU1 76 88 AXLE REAR 2 41 RATIO GU2 76 92 AXLE REAR 2 73 RATIO GU3 82 85 AXLE REAR 2 93 RATIO GU4 76 93 AXLE REAR 3 08 RATIO GU5 76 92 AXLE REAR 3 23 RATIO GU6 76 93 AXLE REAR 3 42 RATIO GV4 82 87 AXLE REAR 3 36 RATIO GV8 82 85 AXLE REAR 2 72 RATIO GW4 B4 85 AXLE REAR 3 31 RATIO GW6 85 89 AXLE REAR 3 27 RATIO GW9 76 92 AXLE REAR 2 93 RATIO GX3 88 93 TRANSAXLE FINAL DRIVE 3 33 RATIO GX4 76 83 AXLE REAR 3 75 RATIO GX5 76 83 AXLE REAR 4 09 RATIO GY5 76 87 AXLE FRONT 3 65 RATIO G44 85 91 AXLE REAR 3 07 RATIO G5O 76 92 SPRING HEAVY DUTY REAR G6O 76 92 SPRING REAR AUXILIARY G66 76 87 ABSORBER AIR BOOSTER REAR SHOCK G66 88 91 LEVEL CONTROL MANUAL AIR G67 76 87 ABSORBER AUTO LEVEL CONTROL SHOCK SYSTEM G67 88 91 LEVEL CONTROL AUTO AIR G72 82 87 AXLE REAR 2 14 RATIO G75 82 87 AXLE REAR 3 62 RATIO G8O 76 92 AXLE REAR POSITRACTION LIMITED SLIP G83 82 83 GEAR RING 8 75 INCH G87 76 91 GEAR RING 8 50 INCH G88 76 83 GEAR RING 8 875 INCH G89 76 87 GEAR RING 7 50 INCH G92 76 93 AXLE REAR PERFORMANCE RATIO G95 85 88 AXLE ECONOMY RATIO HA3 82 89 AXLE REAR 5 29 RATIO HC4 76 93 AXLE REAR 4 56 RATIO HC7 76 93 AXLE REAR 5 13 RATIO HC8 76 87 AXLE REAR 3 21 RATIO HD1 82 84 AXLE REAR 5 83 RATIO HE3 76 84 AXLE REAR 3 07 RATIO HF7 76 92 AXLE HEAVY DUTY REAR 4 56 RATIO HF8 76 92 AXLE REAR 4 88 RATIO HK1 82 86 AXLE REAR 2 87 RATIO HK9 82 84 AXLE REAR 5 86 RATIO HPR 87 92 HEADLAMPS DUAL RECTANGULAR HO4 76 91 AXLE REAR 4 11 RATIO H4D 85 85 EMISSIONS CONTROL 6 CYLINDER SPRING OPERATED EFE 8 CYLINDER CAST IRON EXHAUST MANIFOLD H5D 85 85 EMISSIONS CONTROL 6 CYLINDER VACUUM OPERATED EFE 8 CYLINDER STAINLESS STEEL EXHAUST JA1 76 89 BRAKE SYSTEM LIGHT WEIGHT DISC DRUM JA2 88 91 BRAKE SYSTEM HEAVY WEIGHT DISC DRUM JA3 76 83 BRAKE SYSTEM POWER STATION WAGONS JA3 84 86 BRAKE SYSTEM POWER EXTRA HEAVY DUTY JA5 76 85 BRAKE SYSTEM POWER HEAVY DUTY JA7 86 91 HANDLE PARK BRAKE RELEASE LEATHER WRAPPED JA7 88 88 2 N HANDLE PARK BRAKE RELEASE LEATHER WRAPPED USED WITH SE Y92 JA8 82 87 BRAKE SYSTEM POWER MEDIUM DUTY JA8 88 91 BRAKE SYSTEM MEDIUM WEIGHT DISC DRUM JB1 76 89 BRAKE SYSTEM MANUAL DISC DRUM JB3 76 92 BRAKE SYSTEM VACUUM POWER DISC DRUM JB5 76 92 BRAKE SYSTEM VACUUM POWER DISC DRUM JB6 76 92 BRAKE SYSTEM VACUUM POWER DISC DRUM JB7 76 92 BRAKE SYSTEM VACUUM POWER DISC DRUM JB8 76 92 BRAKE SYSTEM HYDRAULIC POWER DISC DRUM JC4 82 87 BRAKE FRONT VENTED ROTOR JD3 76 87 BRAKE SYSTEM HYDRAULIC POWER DI C DRUM 1990 GENERAL MOTORS SERVICE PARTS OPERATIONS PONTIAC 22W npc 18 REV 6 90