The larger diameter lines will not help. The problem is that the factory pump (no matter pushing or pulling) SUCKS!
Considering my truck has a few miles on the odometer (170,000) I did not want to spend a ton of money and time with the install of the big Airdog or Fass pumps. As long as you don't plan to any big power upgrades, just go with the Fass DDRP (Direct Dodge Replacement Pump). It was easy to install and fixed the low pressure problem.
Either way, good luck.
Considering my truck has a few miles on the odometer (170,000) I did not want to spend a ton of money and time with the install of the big Airdog or Fass pumps. As long as you don't plan to any big power upgrades, just go with the Fass DDRP (Direct Dodge Replacement Pump). It was easy to install and fixed the low pressure problem.
Either way, good luck.