Yes, a ragwing MUST have an operable fuel pump and check valve.
No, you may NOT remove it.
Yes, there are situations where the fuel flow is insufficient in t he ragwing without them, due to fuel system differences.
No, replacing the engine with a later engine does NOT relieve the requirements for the pump and check valve. (It's an airframe thing, not an engine thing.)
Yes, pumps and check valves are available.
Pumps are less expensive NEW than overhauled from Aircraft Spruce 877/477-7823, their PN AF-40585, for $249. (Or if you want the original AC pump in overhauled condition order PN 05-19025 for $267.95)

The check valve, is Republic PN 483-1/4-DI-1/4 available from Sturgis Equipment at Ph: 913/492-2444. (This last check-valve info courtesy of Eric, the Hokey-Pokey Man.)
