On some early Ford engines they were installed bottom down and were indeed sediment bowls. Those were also hard to keep sealed at the top of the clear bowl. You would see gas dripping out when they pulled in to a gas station...always unnerving. Then sometime in the mid or late 50s Ford changed the design of the pump and the bowls had to be mounted facing up when the fuel pump was replaced (or you had to do some clever re-routing of the fuel line). As I recall the new pump design put the bowl too close to the exhaust manifold (especially on sixes) and caused vapor lock.
