Walbro/TI Automotive fuel pumps have various outlet diameters and body lengths.  Fore Innovations fuel pump modules require "cartridge adapters" between the pumps and the pump assemblies for proper o-ring sealing at the pump outlet and the pump inlet is at the same depth for any [compatible] fuel pump installed.

Type A (four different sizes) are used for GSS, F10000, and F90000262 fuel pumps.

Type B (one size) is used for F90000267, 274, 285, and 295 fuel pumps.

See the attached manuals for service of the cartrdige adapters on the outlet of fuel pumps.

Here is a YouTube video that outlines the general process of installing and removing a fuel pump in Fore Innovations fuel pump assemblies.