[dmw_4814]

I'm going to be replacing my fuel tank & pump assembly soon (I have one of those Walbro 255LPH pumps that I bought about 3 years ago, and never even took out of the box), and need to know what goes into the two holes I circled in red in the attached photo. I know the fuel tank vapor vent valve goes in one of the holes (I'm pretty sure), and I'm thinking it's the larger of the two holes. What goes in the other hole? I thought on some earlier models a separate fuel gauge sending unit went in there, but isn't the fuel gauge sending unit on the 2002 Mustangs integral with the pump module/assembly?

Any info would be greatly appreciated! Thanks.