Hi, Ive got a sumped fuel tank, with 2 outlets. 1 im using for the flow out. The question I have, is can I use the other outlet for the return? Or is putting fuel back under the pressure of the weight of the fuel in the tank going to cause a oroblem? I dont think I can get a -10 AN fitting in the top?

 

Personally i don't see a problem as far as pressure goes.
My concern would be returning warm fuel immediately adjacent to the sump pick up point so possibility of raising fuel temp to rails; most likely with extended driving , not a short burst down the strip
I have seen small coolers on the return line installed to get airflow under rear to cool fuel before it gets to tank