Rear gear ratio RPO code list

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02-11-2019, 08:48 PM

burnout88

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Car: 88 IROC

Engine: 305 TPI

Transmission: 700R4

Axle/Gears: 10 bolt 3.73

Rear gear ratio RPO code list

Do we have a master list of the rear gear RPO codes? Did the codes ever change from year to year?

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02-12-2019, 09:54 AM

okfoz

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Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27

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Car: 87 Formula T-Top, 87 Formula HT

Engine: 5.1L TPI, 5.0L TPI

Transmission: 700R4, M5

Axle/Gears: Sag 3.73, B&W 3.45

Re: Rear gear ratio RPO code list

To answer your question, No there were no changes from year to year for RPO codes. GU2 is always 2.73 for example.

As per FIREBIRD PARTS CATALOG, Camaro would be same or similar
1982: - 10 bolt 7.50" Saginaw
GU1 - 2.41
GU2 - 2.73
GU3 - 2.93
GU4 - 3.08
GU5 - 3.23
GU6 - 3.42

1983: - 10 bolt 7.50" Saginaw
GU2 - 2.73
GU3 - 2.93
GU4 - 3.08
GU5 - 3.23
GU6 - 3.42
GT4 - 3.73

1984: - all 10 bolt 7.50" Saginaw
GU4 - 3.08
GU5 - 3.23
GU6 - 3.42
GT4 - 3.73

1985:
GU4 - 3.08 - 10 bolt 7.625" Saginaw
GU5 - 3.23 - 10 bolt 7.625" Saginaw
GU6 - 3.42 - 10 bolt 7.625" Saginaw
GT4 - 3.73 - 10 bolt 7.625" Saginaw
GW6 - 3.27 - 9 Bolt 7.75" Borg & Warner
GM3 - 3.45 - 9 Bolt 7.75" Borg & Warner
GS4 - 3.70 - 9 Bolt 7.75" Borg & Warner

1986:
GU2 - 2.73 - 10 bolt 7.625" Saginaw
GU4 - 3.08 - 10 bolt 7.625" Saginaw
GU5 - 3.23 - 10 bolt 7.625" Saginaw
GU6 - 3.42 - 10 bolt 7.625" Saginaw
GT4 - 3.73 - 10 bolt 7.625" Saginaw
GH3 - 2.77 - 9 Bolt 7.75" Borg & Warner
GW6 - 3.27 - 9 Bolt 7.75" Borg & Warner
GM3 - 3.45 - 9 Bolt 7.75" Borg & Warner
GS4 - 3.70 - 9 Bolt 7.75" Borg & Warner

1987 & 1988:
GU2 - 2.73 - 10 bolt 7.625" Saginaw
GU4 - 3.08 - 10 bolt 7.625" Saginaw
GU5 - 3.23 - 10 bolt 7.625" Saginaw
GU6 - 3.42 - 10 bolt 7.625" Saginaw
GH3 - 2.77 - 9 Bolt 7.75" Borg & Warner (No Firebirds reported with this axle in 1988 no data for 1987)
GW6 - 3.27 - 9 Bolt 7.75" Borg & Warner
GM3 - 3.45 - 9 Bolt 7.75" Borg & Warner

1989:
GU2 - 2.73 - 10 bolt 7.625" Saginaw
GU4 - 3.08 - 10 bolt 7.625" Saginaw
GU6 - 3.42 - 10 bolt 7.625" Saginaw
GH3 - 2.77 - 9 Bolt 7.75" Borg & Warner (No Firebirds reported with this ratio)
GW6 - 3.27 - 9 Bolt 7.75" Borg & Warner
GM3 - 3.45 - 9 Bolt 7.75" Borg & Warner

1990 ~ 1992 - 10 bolt 7.625" Saginaw
GU2 - 2.73
GU4 - 3.08
GU5 - 3.23
GU6 - 3.42