My 440 is a stroked 493 540 solid lift cam with Modern Cylinder Heads ported Stealth heads it needed the xtra volume. The other pumps fell off, and the pump puts out a max 8.5 that doesnt mean you get that psi at idle. My six pack is jetted pretty fat with a 50cc accelerator pump 3/8 line.It needed the xtra volume, the other pumps couldn't keep up and were a waste of money.