D valve wear and choice of metals

[myrickman]

I’m working on a small plunger pump for a model I’m building which has a spring loaded D valve to shuttle fuel from the plunger to the delivery port. For scale, the d valve is a 0.25” cube. The body is made from zinc-based yellow brass and I’m looking for opinions on what to make the d valve from. I’m thinking of cast iron so the d valve wears into the backing plate. As pictured, I originally made it from bronze, but in operation it looks like it will wear considerably. If the mating plate wears, I can easily lap it in to re-seat it. Not shown is the plunger in the plate which mates up with the d valve. Fuel will be light hydrocarbon similar to gasoline with a tad bit of oil mixed in. I do also now have some brass bar stick of the same composition to make the valve from. What is/ are opinions of the steamy guys about dissimilar/similar metals for d valves?