I got mine from OFI last week and finally had some time to install it yesterday, the installation when very quick, I used only the pump, spacer, made a gasket and used some hose to connect the pump to the feed. The line on the 4bt fits just fine on the piston lift pump and I did not have to cut a thing it fits almost tight but is doesn't touch anything so that was even quicker.

Now for the #'s, I can see clearly 8psi at idle and maybe 10psi driving but as soon as I put the foot on it it will go lower (6psi) and on some of the biggest hills around here I could get it down to almost 2psi but not lower so far. For reference the other pump would stay at 5psi idle, 2 psi driving, 0psi on most any hill.
Keep in mind this is a heavy step van with most of My work tools, don't know how it will work on a pickup truck. The lines are a little too long for Me so I will change that soon and post some results I think the pressure will be higher then.

 

So you put this pump on your 4bt, not your 6bt? I thought it would run a little higher pressure, this is a low pressure piston pump right? just a delphi brand instead of a carter/cummins? I'm thinkin about gettin one. Whats the part numbers for the spacer and pump again?

 

I started a thread a couple weeks ago asking about this pumps and the correct part #'s, a couple members have them (also posted the part #'s) and like them but neither have a pressure gauge on their fuel lines. I have electric pumps on My 6bt and the pressure is always good but I thought I would like to go back to a mech pump and this one is ok so far but I need to do a little more testing.
The fuel line to the tank is very long and since the PO did not use a ff with a water separator they installed a racor housing and a filter so the line goes from the tank to this housing then to the filter, I will get the fleetguard filters with the water separator and that will shorten the fuel line about 5'. Also the tank had no vent on it so the old pump was actually pulling vacuum on the tank I noticed this when i opened the fuel cap I could feel the tank taking air IN so I removed a plug they put on one of the lines going to the tank and that fixed that problem.
Also I'm not sure the cam gets to hit a full stroke on the pump, there is a spacer and then the gaskets I'd like to check how far the rod it rides IN to measure if I could shave some space off but that is just an idea.