I know this is a dumb question, on an 02 cummins 5 speed, everything under the hood is stock except for the lift-pump, which is a fass lift-pump, and reading and knowing fuel pressure is everything, how would a big line kit help?

Still not a good idea.   Just because a lot of people steal things doesn't make it right to steal too. Same here just because a lot of people run excessive pressure doesn't make it right either. 21 PSI isn't really bad but 30 PSI is a sign of crappy fuel system and crappy pump.

Or just not adjusted properly. My point was at 21psi the seal isn't going to blow out, and I need to run that high of pressure to keep decent WOT pressures. Next on the list (after twins) is a fass 150 and modified Vulcan liberty fuel module. 

I need a reliable system for the trip in late spring.

Mine will go into red, and I have about 50 miles left. haha

 

Whoops, apparently there was more then one page.

Or just not adjusted properly. My point was at 21psi the seal isn't going to blow out, and I need to run that high of pressure to keep decent WOT pressures. Next on the list (after twins) is a fass 150 and modified Vulcan liberty fuel module. 

I need a reliable system for the trip in late spring.

Anyone using the bean diesel sump?

I don't have a draw straw, but when my light comes on I have 8-10 gallons in the tank.

3/8 lines running from the tank to the stock filter assembly.

Stock line from filter to VP.

Pressure drop from idle to WOT is 11psi or more. (21 to 10 or less)

 

I haven't replaced it because when I put a big boy pump on I'll run all 1/2in lines from tank to VP and use the space from the stock filter to run a breather bottle.

what is a breather bottle?

what is a breather bottle?

Crankcase vent on the front of the gear case.

what is a breather bottle?

I'll run the breather off the front of the engine into a bottle with a filter on the top so it'll quit spitting on my diff. I don't mind the 12v tappet cover dripping every now and then, but I like to keep the front clean.