Fuel delivery/return line size question

[Hutchew]

Looks like I am stuck with running my old gasoline tank on my conversion project, as I cannot make a later model diesel tank fit without unwanted modifications (3" body lift or 3" tank drop... yuck!). My question is will it be detrimental to performance if I run the stock line size out of the gas tank? Original piping in the tank is 5/16" delivery, and 1/4" return. I plan to eventually run @350-375 HP and 8-900 ft pds torque. I can, of course, run larger fuel line out of the tank to the pump and back, but will the smaller lines into the tank hurt me? I am thinking it will, but wanted some expert opinions first. TIA

 

[illflem]

"When in doubt, cut it out" is what I used to tell my guys when teaching them to prune apple trees. I think the same may apply here, the sizes you speak of are marginal I'd bump up to 3/8 or 1/2".