1990 7.3 f350 fuel lines
 

Can someone please tell me where I can purchase fuel lines from the tanks to the lift pump? Mine need replacing. Also which fuel line is return and which line is supply on the top of the engine

driver side rear of the engine is return line, the supply line comes from under the passenger side frame I replaced mine with ptfe or somekind of hard plastic line (it doesnt rot whatever it is) I ordered through napa but you could make your own from rubber fule hose from any parts shop but the rubber rots over time

IIRC it has steel or aluminum lines stock but one of my trucks had the hard plastic lines when i got it and I replaced the other one beacuse I burnt through a line when I was welding a bracket onto the frame took forever to figure out why I couldnt get it started. no problems with the hard plastic I recomend them.

when i ran derby cars i used soft copper ya its pricy but it takes a beating before it will go bad not to mention it takes a long long time to rot like a long time ive got copper lines from 1930 on a swamp buggy we have still strong but alittle brittal where the sun got to it imo if your going to use something other than stock lines soft copper with nice compresion fittins is the way to go not to mention i notice a temp difference in my fuel not on my diesel cause it has stock lines but with other projects