This is the OEM LT1/LT4 MAP Inlet Pressure Sensor mounted on the side of the LT4 Supercharger, closest to the throttle body on a Camaro ZL1 or the MAP sensor on the intake manifold on a Camaro SS/LT1.
General Motors is an OEM manufacturer. GM designs and creates the vehicles and the parts for them for makes such as Buick, Cadillac, GMC, and Chevrolet. All GM branded parts are OEM standard quality components and were designed and manufactured to either be on the vehicle from the factory or purchased after the fact as an accessory.