Are the oil pumps different on a Chevy 350 And 454?

Yes, the oil pumps for a Chevy 350 and a 454 are different. While they might look superficially similar, the 454, being a larger displacement engine, requires a higher-volume oil pump to adequately lubricate its larger components and higher operating pressures. The 454 pump will generally have a larger capacity and may have different internal components to handle the increased flow. Using the wrong pump can lead to insufficient lubrication and engine damage.