The ThermoMaster™ Power Chip is designed to be used with a 160° or 180° thermostat. Hypertech Power Chips are direct replacements for the stock chips in your 1991 Chevy Camaro or Pontiac Firebird. 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. 1981-1995 GM automotive computers used replaceable PROMs or chips to calibrate the Electronic Control Module (ECM) for specific engine, powertrain, and vehicle combinations. Hypertech created the original Power Chips™ to recalibrate these electronic brains for improved performance. As interest in Power Tuning™ grew and the variety of OEM systems increased, Hypertech developed innovative products to complement the increasingly complex on-board computer systems. From Camaro, Firebird, Malibu, Corvette, Caprice, Truck and other GM vehicles, we have what's right for you. Look for these brands to get your project running right!