What do the FASS part numbers mean?

The first number represents the model or series. The HPFP is only the fuel pump. The 95 series and 150 series are both complete systems with a fuel filter and water separator attached. The 95 series has a smaller base with smaller filters, while the 150 series has a larger base, larger filters and more readily available aftermarket filters. The second number represents the gallon per hour flow rate of the system. The number after the dash reflects the specific application that the system is designed for.