I'm using my stock fuel line for the return line without any problems and a -6an for my feed. I have a fuel pressure gauge on my feed and another on the return and both read great, so I am not seeing any restrictions on the return line. If I am recalling correctly it is reading somewhere around 3 psi or a little more on the return.ya i thought i could use the return thats on there but the tech i talked to said you'll get better performance and life out of your fuel pump with a 3/8 return. I dont have my kit yet but i have all the lines, fittings sending unit ,pump and filter.
I will order the kit in 18 days(going fitech). i want it so bad. its starting to get in the 90s here and the hard starts are a p. i. t. a.
I used the factory supply and return lines.
Yes, TBI originally. The supply lines are 3/8" and the returns are 5/16".TBI truck right? Some of us are carb or diesel.....