Fuel system questions...

[Jstock85]

Got an 85 c10 with carb and mechanical fuel pump. Plan to swap 4.8 vortec from a 2000 chevy truck. Ive pretty much got everything covered wiring, exhaust, cooling, ect... I have a few questions about the fuel set up. I've heard in tank systems are better the in line systems. First id like to know how true that is. How many of you guys have in line systems and how many problems are you having? My main question is can I get an 87 and up tank (with built in sump) and use my sending unit with a Walbro or Aeromotive pump installed to it?

Or just any advice on how any of you guys built your fuel systems would help!

This truck is just daily driver. nothing high horse power or racing or any of that.

[LSSierra]

I used my stock 87' sending units with the AC Delco high pressure pumps and my guage works for both tanks. Had to get the high pressure fuel switch valve (if you are using dual tanks). Used stock fuel filter in line on the frame. Haven't had any issues.

[Jstock85]

Thanks for the reply! So I can basically swap tanks, modify the sending unit with a electric pump, connect lines and filters and should be good to go? What about a pressure regulator?

[69gmcc10]

To answer your first question about internal vs external pumps. Internal pumps are cooled by the fuel and external pumps are cooled by the temp of the air around it. When you are real hot do you want a warm breeze blowing past you or do you want to jump in the lake? The liquid fuel draws heat away from the pump way better than air making it last longer. internal pumps have 1 job to do and that is "push" fuel, external pumps "suck" fuel from the tank and "push" it up the fuel line, and as we all know from Ron Swanson "it is better to whole ass one thing than half ass two things." It is also easier on a pump to push than pull, adding to the longevity of its life.

External pumps work and work well but do not seem to be as reliable as in tank pumps.
But the bigger point than any of this is just what LSSierra said, your fuel delivery issues are a pretty simple fix. Double check this info, but 87s were tbi engines and had a baffle and lo pressure pump in the tanks. If you pull the sending unit our of your tanks and replace just the lo pressure pump with an AC Delco EP381 pump that is the same dimensions as the lo pressure pump, all you need is a high pressure switch to move back and forth between tanks and maybe corvette fuel filter (I am not quite sure) and you are in business and the fuel gauge should work like nothing ever happened.

good luck!

[Jstock85]

I have single tank so I'm ok there. What about pressure regulator? What do you recommend there?

[69gmcc10]

It depends on your engine, later LS engines have a returnless system on top of the engine at the fuel rail and the corvette filter acts as the regulator and provides the return line to the tank.

Older LS engines have the regulator and the return line at the top of engine at the fuel rail and you need to run the return line from there.

[Jstock85]

I'll check that out. It's out of a 2000 chevy truck.

[69gmcc10]

there is a return at the fuel rail on that engine, so the original stock fuel filter on the rail should do you just fine.

[izzy_Britton]

THIS might help...

http://67-72chevytrucks.com/vboard/s...14&postcount=7

rest of the thread here...

http://67-72chevytrucks.com/vboard/s...highlight=fuel


in your case you dont have to worry about the dual tank info, but the rest should be straight forward...

Izzy

[mongocanfly]

On my 81 I used a walbro 255 external pump..that goes ino a vett filter/regulator..the return side of the filter/reg goes right back into the tank..only one fuel line running from tank to the rail..my original 350 engine was a pump return setup so my sending unit already had a return hose fitting on it..my lq9 6.0 is a return rail system..I simply capped off the return rail with
-an fittings and cap..as far as reliability I've got about 20k on it with zero issues..