I suspect that it's either GSS250 or GSS242 but I figured who better to ask than Mustang people themselves?

Yeah, I know I might look lost on here with a Crown Victoria, lol, but here's the deal:

My fuel pump is dying very rapidly and I need a replacement, the Motorcraft replacement is at least $350 and out of the question, and I've heard nothing but Walbro pumps for replacements but unfortunately they only make a 255lph model for the Crown Victoria(and I'm not even sure it's not just a modded Mustang one), which runs extremely loud at all times and also doesn't work very well for very long in 02 and earlier Crown Vics that don't have a returnless system(added 03+ on Crown Vics) due to the less flexible way the return-style system handles the pressure. I can still use a pump for returnless systems, but 190lph is the largest common size that the fuel system is designed to be able to still tolerate on my car.

You guys have a 190lph model Walbro makes for your cars though, and a popular choice for people on the Crown Vic forums is to slightly modify the sleeve on the 255 model for the Mustang to fit in our cars pump assembly, so I figured I might as well just do that with the 190 model on mine.

 

http://www.fuel-pumps.net/ford.html