1LE was created by Chevrolet to homologate Camaros for SCCA Showroom Stock Endurance racing — a category that required a minimum number of street-legal production cars to qualify a model for the series. The package bundles parts that competition Camaros needed but the regular Z28 / IROC-Z didn't: an oil cooler (KC4), the 3.42 G92 Performance Axle Package with limited-slip (G80), an aluminum driveshaft, a baffled fuel tank that stopped fuel starvation in long left-handers, and the 1LE-specific brake package — PBR-derived 4-wheel discs with larger rotors, twin-piston front calipers, and ducted cooling.
1LE was orderable only with the manual transmission for most years (the MM5 Borg-Warner T-5), and only with the L98 5.7 TPI or LB9 5.0 TPI on a Z28 / IROC-Z platform. It was never advertised — buyers had to know to ask, and dealers had to know what RPO box to check. About 478 documented cars were built across the 1988–1992 production run. Real 1LEs are rare and identifiable by VIN + SPID label callout; many fakes exist (regular IROC-Z cars retrofitted with later 1LE brakes), so the SPID is the load-bearing identity check.
The 1LE option carried over to the 4th-gen Camaro starting 1993 and is still offered (in different form) on modern Camaros. The 3rd-gen 1LE is the original.