Performance/Optional Rear Axle Ratio

Years 1963–79 Models 4 Factory citations 6

Also described as Performance axle ratio (dealer ordering code)Performance axle ratio (4.10:1)Rear Axle - Performance RatioRear axle

Documented applications

Camaro

1968–1969 Factory-verified

powertrain dependent

GM Heritage factory kit — 1969 Chevrolet Camaro, p.158.
1970–1972 Factory-verified

requires G80 and L78 or Z28

GM Heritage factory kit — 1971 Chevrolet Camaro, p.27.

Chevelle / El Camino

1970–1972 Factory-verified

GM Heritage factory kit — 1971 Chevrolet Chevelle, p.31.
GM Heritage factory kit — 1971 Chevrolet El Camino, p.58.

Corvette (C3)

1971 Factory-verified

$12.65; 2,395 built. Code was disputed (CAC/CorvetteStory split ZQ9 vs ZQ1). Factory kit resolves: the price schedule (p.70) lists economy axle **ZQ8** and performance axle **ZQ9** at $12.65 each — "ZQ1" does not appear anywhere in the kit

GM Heritage factory kit — 1971 Chevrolet Corvette, p.70.
1972 Factory-verified

$12.65 (early-year $12.00); 1,986 built. Code was disputed (CAC = ZQ9 vs CorvetteStory/CorvSport = ZQ1). Factory kit resolves: the price schedule (p.76) and Extra Cost Equipment list (p.98) both show economy **ZQ8** / performance **ZQ9** at $12.65 — "ZQ1" does not appear in the kit

GM Heritage factory kit — 1972 Chevrolet Corvette, p.76.

Impala / Full-Size

1963–70s (varies) Confirmed

Performance ratio

This page aggregates every documented appearance of ZQ9 in the Chevrolet reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.