Fuel line options.... new return or new feed? Dual walbros.

Alright i'm ready to put these walbro 255's in and cannot decide what to do... I am thinking of running a new 8AN feed and using my existing returnless "feed" as the new return line for purposes of keeping my factory fuel composition sensor to keep the ECM happy for E85 use. I'm going to be at about 12-14psi on 75lb injectors for right now. Would i be better off using a bulkhead and running a new feed and using the current feed as the return after the regualtor.. or should i run a new return line and use my existing feed? the line going into the composition sensor is the same as the line.. but the line coming out of the composition sensor is very small! looks like a serious restriction to me. I'm sure someone will say use the EVAP line as the return... but i hear a good many stories of tank pressure and venting problems. I Have even contemplated keeping the system returnless and running the second pump off a hobbs switch, so as not to heat the fuel when all that volume isn't needed... Thanks in advance for any help..... this is really beating me in the head! :smash:

I used -8 feed and -6 return. I used the stock feed for the feed, and drilled a hole for a bulkhead for the return. Then drilled another hole to wire it up. Use a gromet and goop seal crap to seal it up for evap.

BTW mine was a dual walbro set up on 12 psi and 48# injectors. Fuel kept up just fine.

I have a flexfuel truck and i am trying to figure out how to keep my fuel composition sensor to keep my E85 compatibilty so i can run any mix of fuels anytime. Its very plentiful around here and extremely cheap compared to gasoline, and it loves boost. Thats why i was thinking of using my current feed line as the return and reversing the lines on my fuel composition sensor so fuel still flows the correct way through the sensor but is actually returning back to the tank.

This way i would simply need to plumb an 8AN line as my feed from a bulkhead on top of the sending unit, and purchase a 3/8 to NPT fitting and just hook it straight to the return port on the regulator.

I don't see why that wouldn't work. But then again I really don't know about flex fuel.