What is tri power in a 389 Pontiac?

"Tri-Power" in a 389 Pontiac refers to the three two-barrel carburetors used in the engine's intake manifold. Instead of a single four-barrel carburetor, this setup utilized three smaller, two-barrel carburetors, each feeding a portion of the engine's cylinders. This was a performance option that offered increased airflow and horsepower compared to a single four-barrel, especially at higher RPMs.