Hypertech ThermoMaster Power Chips are engineered for stock 1995-1981 GM vehicles (premium octane fuel required). 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. ThermoMaster Power Chips are designed for daily street driving or competition in unmodified vehicles using a 160-¦ or 180-¦ thermostat. Hypertech Power Chips(TM) are emissions certified 50-state legal (application specific).WARNING CA Proposition 65: YesWARNING CA Proposition 65 Message: WARNING: Cancer and reproductive harm. Visit www.p65warnings.ca.gov