General Motors uses two methods of naming cylinder banks in V engines.

For emission related components, cylinder banks are named using a Society of Automotive Engineers (SAE) recommended practice.

Bank 1 is the cylinder bank that has number 1 cylinder, and bank 2 is the cylinder bank that does not have cylinder 1. Cylinder 1 location is given in service manual service category Engine Mechanical, within Engine Component Description.

For other than emission related components, cylinder banks are named Left and Right.
This is determined by looking toward the front of the engine from the flywheel end.
This method is used whether the engine is installed longitudinally or transversely.