I am going to be running in the 600s. on3 kit 76mm, they say their 340 will do just fine on a return less system. i hear horror stories about short lived pumps. what other brands are similar in flow but will last? i dont mind paying for it if its good quality.

these are some of the pumps ive found. which would be the best ?

stealth 340 340lph
denso 1020 300lph
on3 340lph
bosch 044 300lph
aremotive 340lph
aem 50-1000 320lph

 

check out the racetronix 340s too. i have one ive been running for a while and its kept me happy. not sure where ive been power wise. probably in the 500 range. i log fuel pressure and have never seen it fall off.

 

If your fuel pressure never falls off then you have a return system

 

Im running a 450 in my truck.

 

are the returnless systems not boost reference?
i had an aeromotive regulator down on the frame rail near the tank with a single line going up to a 'returnless' style rail.

 

No they are not referenced. The regulator is in the tank.

 

so i noticed on my avalanche motor ( one going in my silverado) there are 2 lines on the fuel rail. i assume this is the return line and main line. other than getting the wiring upgrade kit i and making a return line to the tank, i should be able to convert to a return style system with little work.

 

well thats dumb. i wouldnt use that with boost.

 

Im running a stealth 340 in a returnless system which worked well for 6-7psi. I pullied down and made close to 10, and my fuel pressure dropped into the high 30's. Im making just shy of 600rw through a procharged 6.0. Also consider a hotwire kit.

 

If you have two lines on the fuel rail then you already have a return. What year is it? 03 and down were return.