I found a store brand of garden-hose stainless filters that fit well. Or get some SS mesh and form your own. I've noticed some original Ford pickup (main) filters are much finer than others, and although I haven't proven anything (or tried to), perhaps the pump intake filters were used with coarse main filters? Anyway, I now skip those and use a Magnefine inline filter and a fine-mesh pickup filter to keep it all clean. And don't forget to use the governor filter. I found some fuel injector filters (the kind that go into the injector) can work there if your supplier doesn't carry them.
I'll have to look into the garden hose filters. I haven't had any problems getting the governor filters.
I build early Bronco C4s and those seem to have had the filters from the factory. I use other C4s for parts only. I assumed all C4's had them originally. I think they do a good job of keeping junk out of the valve body.