Chevrolet introduced the now-famous IROC-Z model in 1985 (IROC = International Race of Champions).  The main focus was a vastly improved suspension: lowered springs, custom-valved shocks, larger diameter sway bars, and 16-inch wheels and tires identical to those on the Corvette.  The IROC-Z also received the 215 hp Tuned Port Injection (TPI) 305 cubic-inch V8 and 700-R4 automatic transmission.  All Camaros received updated exteriors for 1985 in the form of a redesigned front end.