David,
Having just spent $$$$ for a new VP and LP at the Cummings dealer I have decided to finally move the LP down to the rail. I've ordered one of the kits from one of the advertisers here. And after reading the "Pumps, Lines, and Whatnot" thread, and checking all sorts of configs on numerous sites like Barry Grant, Aeromotive, etc. , I've realized that there must be a filter pre-pump. I always figured and trusted, however stupidly, that the pumps were designed to handle that sort of thing. Most of the racing suppliers highly recomend a filter pre-pump to protect the pump. Makes sense to me. I've always put filters pre-pump on my race cars to protect those high $$ racing pumps.
My last LP had good presure, 14. 7 idle and 12. 5 at 70MPH @2500 RPMS, but no volume according to the Cummins boys. Once I took it apart, I found scoring between the rotor vanes and housing, leading me to realize that there was indeed trash coming into the pump from the tank, even with the stock "sock" on the pick-up.
I've got some new parts coming from my kit supplier mentioned above that will be testing for him prior to release to the general public. Sort of a "Beta" test.
This will hopefully deal with the flow issues, clogged in tank socks, presure, and volume to the VP44. I will also be adding a pre-pump filter. The Fleetguard unit FS1212 is, according to the Fleetguard website, designed for suction side applications, provides 20 micron filtration and water seperation duties. The spin-on style seems easy to change as well.