Hypertech Power Chips are direct replacements for the stock chips in 1981-1995 GM vehicles. The Power Chip contains the Hypertech Power Tuning data that controls the engine's air/fuel ratio and spark advance for maximum power and performance, plus potential gas mileage improvements. Power Chips can be easily installed, using only hand tools. Street Runner power chips are designed for daily street driving or competition in unmodified vehicles using a stock thermostat.