Well, what the heck, I'll throw our experiences into this pile as well.
Since us Canucks seem to have an even worse time of lift pump failures than our southern cousins, I took the time to pull apart 11 failed pumps that were sitting at my local Dodge dealership. In 8 cases, we discovered that the internal bypass had been well beaten, and that the pumps were kicking into a constant bypass mode, thus reducing fuel pressures to below minimum requirements. 2 of the other cases were related to bushing failure, and the 3rd was indeterminate.
Since the bypass valve was the obvious failure point in most cases, we decided (after talking with Carter and another pump manufacturer) that the long draw from the fuel tank was not causing the problem, but high outlet pressure on the lift pump was cauing the bypass to function more than it was designed to function. We then theorized that the restrictive lines/banjos from lift pump to injection pump was our problem. Techs from Carter agreed with us.
As a favor to me, the local Dodge dealer installed some high flow bolts on trucks that were seeing an inordinate number of lift pump failures. These were generally trucks used in heavy towing, and both were stock powered units. Lift pump longevity went from 20K to 80K, with no failure thus far.
We thought we had it beat, but after putting EZs and DD2's on trucks, the lift pumps began failing again. Trucks with EZs and RV275s appeared to be just fine. So, against my better judgement (pusher assemblies in ag equipment have a terrible reliability record), we tried a couple pusher assemblies using Carter pumps. Lift pump longevity seemed to be better, although pressures did begin dropping, however we ran into pusher failures in our harsh climate. The road salt and water ate the guts of the pusher pumps.
Then we switched to using Holley Black pumps, mounted in the stock location, and using 1/2 ID lines from the Black pump up to the injection pump. Last year, this worked like mad. We've got several 500 HP+ trucks, a couple with over 100,000 miles on them, and pressures are as good as the day they were installed. Again, we thought we had it beat.
Early this year, we attempted another 10 installs of Holley blacks with large lines. 8 of these installs were DOB (dead out of box). Unfortunately, after contacting Holley, we received the company line that their pumps weren't rated for diesel fuel, and as such, their warranty would not be honored. We pulled apart a couple pumps, and discovered that the internal bypass valves had some very rough edges that needed cleaning up and the bypass assemblies needed to be cleaned up with carb cleaner as the valves would stick open. After performing the procedure on a couple pumps, pressures went back to 16PSI at idle, 14 at WOT on 400HP+ trucks. But the experience with Holley has left us with a bad taste in our mouths. Two of our customers felt the same way, so they installed the Holley kits with factory lift pumps, and discovered that pressures were 16 PSI at idle, 12 WOT on their 375 HP trucks. Each has been running with this assembly on their trucks for ~20K now, and pressures have not begun to back down.
The Black changeover kits are a real bear to install on a factory lift pump equipped truck, so we found some custom 12mm to -8 fittings whose internal IDs are larger than any commercially available fittings. We're using these fittings in concert with 90 degree sweeps and -8 braided line, and feel this rigging will work well to the 375 HP mark. We don't feel that there is anywhere near enough vacuum being drawn by the factory lift at these horsepower levels to damage the pump.
For guys over the 375 mark, talks with Product Engineering out of California lead us to believe that these pumps will work great in our application. The PE pumps can draw long distances, as long as their inlet is no more than 1. 5 feet above the pickup, are warrantied for 2 years in diesel fuel applications, and are simply the best built pump I've seen in a long time. We're building a bracket mount the pumps on the frame rail, under the hood for ease of hookup as well as protection from the elements, and the stock line size from the tank to the lift pump will be plenty large enough to supply all the fuel the pump wants. The aforementioned -8 lines will be used to supply from lift pump to the injector pump.
Attention: TDR Forum Junkies 
