Where is the oil sending unit located on 1981 Pontiac Bonneville 265 engine?

The oil pressure sending unit on a 1981 Pontiac Bonneville with the 265 cubic inch (4.3L) V6 engine is typically located on the engine block, near the oil filter. It's a relatively small unit with one or two wires connected to it.

However, without seeing the specific engine, it's difficult to give an exact location. A repair manual specific to that year and engine would be the most accurate resource. You can also try searching online for images of a 1981 Pontiac Bonneville 265 engine to get a visual reference.