If your fuel pump is marginal with respect to PSI, there is a rare chance that you might get fuel starved with the filter on the inlet side of the pump. SUPPOSEDLY, the pump pushes better than it sucks.
I found this out two summers ago, when I was fuel starved in a dual carburetor set-up. I was instructed to put the fuel filter on the "push side" of the fuel pump (I had tried two new fuel pumps). This solved my problem.
