The ZR1 special engine package was a $1,221.00 option available exclusively with the LT-1 engine option. It included the solid-lifter small-block engine, heavy-duty four-speed transmission, power brakes, aluminum radiator, and a revised suspension with special springs, shocks, stabilizer bar, and spindle-strut shafts. Since it was competition equipment, the ZR1 could not be ordered with power windows, power steering, air conditioning, a rear-window defogger, wheel covers, or a radio. Only 53 1970-1972 ZR1's were built (25 in 1970, including 8 convertibles, 8 in 1971, and 20 in 1972).