Custom fuel tank install question

[Pistolgrip426]

04.5 , 6.0,F 550 cab/chassis, has a tow/wrecker body since new. Rear factory tank discarded when new, have GMC saddle tank with custom pickup straw, and utilizes factory fuel guage. Tank is small and i have room for a custom tank to be built to fit above deck. Thinking of using low sump and gravity feed to stock hcfm. Where does factory return line go ? Do i need a bung installed on top of new tank? The tank will be a perfect rectangle shape and fuel supply will run downhill to the factory pump. I will install a safety shutoff valve, but no extra filters. Fuel system is stock other than blue spring. Should i have baffles built into the tank as well ? Thanks.

[ZMANN]

I think baffles are a nice add so the feed line never sucks air ,,

the return is usually plumbed down low also so it doesn't aerate the fuel when dumping back in to the tank ,,

you will need a vent of some sort and I would have a shutoff so you can open the system if need be and not take a bath.. but I think you mentioned that


while not a completely legal set up like oem with suction draw and roll over valves you should be fine

[Pistolgrip426]

Thanks for the reply, when looking at the xdp sump, i only noticed one fuel fitting. So, what you are saying is i can basically install the return bung beside the supply ? It's kinda' like a fuel cell for a drag car? This is what i am picturing in my mind. I was going to have the welder/fabricator build the sump into the tank, with a stainless screen inside, to catch any big chunks, and use the factory filters to catch the smaller stuff and water.

[ZMANN]

make sure you can access that screen have an access panel built it

the guys running sumps on an OEM still have their sending units wit returns they just re rout the feed to the bottom

it's best to have a length of steel tube from the return to the bottom of the taink to prevent aeration

[Pistolgrip426]

Aren't rollover valves just screwed into the top ? I see alot of p/up trucks with aftermarket tanks in the bed? I could still use my pickup tube, mine isn't factory, when we fabbed it, we left the tube long, so it has a mild bend and the opening is parallel to the tank bottom, instead of being straight and cut off close to the tank bottom.

[Pistolgrip426]

I see what you guys mean about the return ,it can come into the top, just have a tube to route it below the lowest fuel level to prevent aeration.

[Pistolgrip426]

And yes a factory tank is impossible, due to wrecker body, i suppose i could utilize my present fuel pickup for the return , and also my fuel guage. Just install it in top of the new tank. And put supply in sump.

[ZMANN]

thats what i would do unless your new tank is so big you need a different sender length

I think you avoid putting the return in the bottom because it would actually fight the return flow ,, so you come in at the top and then take it to the bottom

[Pistolgrip426]

I didnt spec the tank measurements yet for the welder. We can build the tank around the sending unit. I have alot of room for the tank to fit, so i can make the height to equal the sending unit., and just make it longer/wider, as long as i can fit 100-125 gals., i'm ok.