Carb fuel filters

The EFI practice is to run a 100 micron filter before the electric pump and a 10 micron after it to the injectors. They deal with much smaller crap than a carb or check valves in a mechanical pump. Mechanical pumps would be fine with a 100 micron pre pump filter and a 40 micron carb filter. EFI pumps offer low vacuum and they can pull through a 100 micron easily so the high vacuum of a mechanical should pull right through no problem as it already pulls from ~10 feet away in dinky 5/16 line as it is. The sintered bronze rating was 40 for a GM QJ. Their trouble (?) was the small surface area of the filter element, not the material.