Chevrolet Camaro IROC-Z
For 1985, Chevrolet introduced a new Camaro model — the famous IROC-Z, named after the popular competition International Race of Champions. Offered as an option package on the Z28, the Camaro IROC-Z featured an upgraded suspension with lowered springs, specially valved Bilstein shocks, larger diameter sway bars, a lower tie brace, a special decal package, and an optional Tuned Port Injection system taken from the Corvette. It also shared the Corvette's Goodyear "Gatorback" unidirectional tires in a 245/50/VR16 size vs. the Corvette's 255/50/VR16 size, and received unique new aluminum 5-spoke 16 by 8 inch wheels. The new wheels were designed with different offsets front and rear, resulting in the words "Front" or "Rear" cast into the face of the wheels to distinguish which wheel went where.
The Camaro IROC-Z was on Car and Driver magazine's Ten Best list for 1985. The 305 c.i. 5.0 liter TPI LB9 was rated at 215 hp (160 kW) with the 305 LG4 at 155 and the High Output "Rochester" 4 barrel 305 L69 at 190 hp (142 kW). The LB9 was available only on the Z28 and the IROC-Z model with the TH700-R4 automatic transmission.
Also new for 1985, all Camaros featured refreshed noses, and new deeper valances and front spoiler for the Z28 and the newly introduced IROC-Z. The speedometers no longer had the unique double-pointed needle that simultaneously read mph and km/h: they were replaced by conventional single-pointer 85 mph (137 km/h) units. The 2.8 L V6 became fuel-injected, raising power from 112 hp (84 kW) to 135 hp (101 kW). This would also be the final year for the less popular base-model 151 cu in (2.5 L) 4-cylinder engine. The G92 (3.42:1 axle ratio) only available on the LB9 with automatic transmission for 1985 and there were only 205 made.
For 1985 a (1C5) RPO California IROC-Z was also made, Chevrolet's California Marketing Group came up with the idea and it was for sale in California only. A total of (100) black and (400) red examples were produced. They were all equipped with the 5.0 TPI LB9 engine and TH700-R4 automatic transmission. They all came equipped with the IROC-Z fog lights, wheels and ground effects, but with the base Camaro's hood (no louvers), rear decklid (no spoiler), and no exterior decals.
Source: Wikipedia, 2011