Where is the governor on a 5.7L v8 Chevy Tahoe?

The governor on a 5.7L V8 Chevy Tahoe (and most modern vehicles) isn't a physical, mechanical device like in older cars. The engine speed and torque are controlled electronically by the Powertrain Control Module (PCM), also known as the Engine Control Unit (ECU). So there's no single "governor" part you can point to. The PCM uses various sensors and inputs to manage engine speed and prevent over-revving.