planning out dual tank fuel system for LS swap

[heavy71chevy]

So im plannin out my fuel system for my 81 c10 6.0 swap.Im tying to retain my factory dual tanks and keep the price low.My plan is to plumb an electric fuel pump into the supply line right after the selector valve to feed a corvette fuel filter/regulator.Would it do any harm to just cap my return line alltogether?this is more then likely just a setup to get it rolling again and im not looking for perfect just funtional.My stock tanks are oem so theres no baffles for intank pumps so thats limiting my options.Ive been looking at alot of different inline pumps and mainly focused on the 255 pump because my setup is bone stock so 350 is right at my target area which wont take much to feed.Thanks any advice/Input much appreciated

[kipps]

The corvette filter/regulator must have a return. On that regulator, the inlet and the outlet are directly connected to each other. The way it regulates the pressure, is by varying the amount of fuel allowed to go out the return outlet. If the pressure drops too low, the return outlet is blocked off. Is the pressure gets too high, the return outlet is opened up.

You will need a six-port selector valve. Three of the ports are switching the fuel inlet, and three of them are switching the return.

Also, those inline pumps don't like to suck fuel any distance at all, I'm told. I'd be skeptical about pulling through the selector valve and all associated piping.

[Big Chip]

The tanks from 87 trucks are baffled and are direct replacements. I don't remember if the switching valve is the same as the 81 right off the top of my head but I believe it's the same.

[TrybalRage]

Originally Posted by heavy71chevy

So im plannin out my fuel system for my 81 c10 6.0 swap.Im tying to retain my factory dual tanks and keep the price low.My plan is to plumb an electric fuel pump into the supply line right after the selector valve to feed a corvette fuel filter/regulator.Would it do any harm to just cap my return line alltogether?this is more then likely just a setup to get it rolling again and im not looking for perfect just funtional.My stock tanks are oem so theres no baffles for intank pumps so thats limiting my options.Ive been looking at alot of different inline pumps and mainly focused on the 255 pump because my setup is bone stock so 350 is right at my target area which wont take much to feed.Thanks any advice/Input much appreciated

Not sure if you're on Facebook, but there's an LS swapped square body group that has a ton of good info. There was a post just the other day where someone was asking about this. This link was shared breaking down how to keep a selector with dual tanks - https://www.facebook.com/groups/2678...c_location=ufi

Note that it's for running in-tank pumps with +87+ tanks.

[heavy71chevy]

Originally Posted by TrybalRage

Not sure if you're on Facebook, but there's an LS swapped square body group that has a ton of good info. There was a post just the other day where someone was asking about this. This link was shared breaking down how to keep a selector with dual tanks - https://www.facebook.com/groups/2678...c_location=ufi

Note that it's for running in-tank pumps with +87+ tanks.

No hadnt seen that but appreciate the link.looks like I need to find an 87-91 tank.might do away with the duals to make it simpler

[heavy71chevy]

Originally Posted by kipps

The corvette filter/regulator must have a return. On that regulator, the inlet and the outlet are directly connected to each other. The way it regulates the pressure, is by varying the amount of fuel allowed to go out the return outlet. If the pressure drops too low, the return outlet is blocked off. Is the pressure gets too high, the return outlet is opened up.

You will need a six-port selector valve. Three of the ports are switching the fuel inlet, and three of them are switching the return.

Also, those inline pumps don't like to suck fuel any distance at all, I'm told. I'd be skeptical about pulling through the selector valve and all associated piping.

Yea wasnt sure if a holley blue pump would work out better.prolly just gonna cap off my right now and just run one for now.you think it would work with dual pumps wired to use the passenger tank as a feed tank for the other as like a reserve?

[kipps]

Originally Posted by heavy71chevy

Yea wasnt sure if a holley blue pump would work out better.prolly just gonna cap off my right now and just run one for now.you think it would work with dual pumps wired to use the passenger tank as a feed tank for the other as like a reserve?

This is commonly done, to just use a transfer pump to fill the primary tank from the secondary. If you're doing this, at least one of the factory dash switches('87+ would be the best bet, but some others may work as well) should be fine for operating this transfer pump. I would definitely want an indicator light wired in, so I don't forget the transfer pump is running.

[Mattchu60]

I just did dual tanks with 5.3 swap. I have 87' TBI tanks (EFI tanks) with the stock 87' sender, and a EP381 Delco fuel pump which fits right into the spot where the stock 87' pump would fit, but it puts out the needed high psi the LS needs. I have a stock 5.3 fuel regulator on the fuel rail, so I have both the pressure and return lines running to the engine.

I have a new switching valve which is rated for mid-60s psi and it plugs into the stock 87 wiring harness. I replaced all the lines with gates EFI rubber hose from the tanks to the switch valve, and then AN line from the switch to the engine.

Lastly I moved the switching valve to the driver side so the lines can run down the driver side of the frame and up to the fuel rail which is on the driver side of my engine. That's not required but its what I did

[heavy71chevy]

Originally Posted by Mattchu60

I just did dual tanks with 5.3 swap. I have 87' TBI tanks (EFI tanks) with the stock 87' sender, and a EP381 Delco fuel pump which fits right into the spot where the stock 87' pump would fit, but it puts out the needed high psi the LS needs. I have a stock 5.3 fuel regulator on the fuel rail, so I have both the pressure and return lines running to the engine.

I have a new switching valve which is rated for mid-60s psi and it plugs into the stock 87 wiring harness. I replaced all the lines with gates EFI rubber hose from the tanks to the switch valve, and then AN line from the switch to the engine.

Lastly I moved the switching valve to the driver side so the lines can run down the driver side of the frame and up to the fuel rail which is on the driver side of my engine. That's not required but its what I did

You have a link to the switching valve by chance?

[hatzie]

Originally Posted by heavy71chevy

You have a link to the switching valve by chance?

The new motorized Pollack valves should be rated for 65PSI.
You'll want to check the rating before you take it out of the store.

[Mattchu60]

That is correct - I got a new pollak valve. Had a sticker that it was 65 psi rated on it - I bought mine off ebay.

[rodstored-72]

Originally Posted by Mattchu60

I just did dual tanks with 5.3 swap. I have 87' TBI tanks (EFI tanks) with the stock 87' sender, and a EP381 Delco fuel pump which fits right into the spot where the stock 87' pump would fit, but it puts out the needed high psi the LS needs. I have a stock 5.3 fuel regulator on the fuel rail, so I have both the pressure and return lines running to the engine.

I have a new switching valve which is rated for mid-60s psi and it plugs into the stock 87 wiring harness. I replaced all the lines with gates EFI rubber hose from the tanks to the switch valve, and then AN line from the switch to the engine.

Lastly I moved the switching valve to the driver side so the lines can run down the driver side of the frame and up to the fuel rail which is on the driver side of my engine. That's not required but its what I did

I am in the process of installing a '13 4.8/4L60E in my '86 and I have 2 of the EP381 to go with my dual new '87 tanks. If I understand right the '87 stock sender will work with the 381?? it sounds like the above is what I want to do as well??
thanks!!

[Mattchu60]

Yes- the EP 381 will fit right into the stock sending unit. Its physically the same as the stock TBI pump.

One thing I did - may be overkill - but I also got a 1 ft piece of submersible EFI fuel hose. I believe its actually 5/16 and not 3/8 in the tank as well. Common issue is that the stock hose they send you will slowly degrade and eventually burst, causing you to lose all fuel pressure.

[hatzie]

Originally Posted by Mattchu60

Yes- the EP 381 will fit right into the stock sending unit. Its physically the same as the stock TBI pump.

One thing I did - may be overkill - but I also got a 1 ft piece of submersible EFI fuel hose. I believe its actually 5/16 and not 3/8 in the tank as well. Common issue is that the stock hose they send you will slowly degrade and eventually burst, causing you to lose all fuel pressure.

Not overkill at all. If it's inside the tank use SAE J30R10 hose. Anything else will fail much sooner than the correct hose.
Don't buy any more than a foot or so. You shouldn't use it anywhere outside the fuel tank. The outer jacket doesn't have Ozone and thermal resistance characteristics for exterior use.

Use SAE J30R9 hose for fuel injection runs outside the tank with German Fuel Injection clamps or Oetiker ear clamps. The downside to the Oetiker clamps is they are one use and throw away. SAE J30R9 hose is 100psi max working and 900psi burst IIRC. Whatever you do don't use worm clamps on hoses smaller than @ 5/8" ID.

This is my hoses and clamps writeup where I attempted to list most of the common SAE hose types and what they are used for along with some of the more common hose clamps.
http://67-72chevytrucks.com/vboard/s...d.php?t=696742

[rodstored-72]

ok guys, I am in the process of installing the 381 in/on the '87 sender. I have a few questions - I am not familiar with these pumps/ senders. I would really appreciate some pointers on installing them some of the following:
1- the feeder tube from 381 "butts" against inline with feeder tube from sender?
2- how do the clamps included with the 381 work?
3- the "foam" sleeve included with 381 slips over the elect. conn and hose assy. and butts against rubber sleeve on the top of 381
4- the rubber base sleeve fits the 2 tabs on bottom of 381 which pinches between circular base of sender?
5- the white filter with steel ring slips over the circular bottom portion of 381

the gap between 381tube and sender tube appears to be about 1/8"??
I assume the electric conn to pump is able to be submerged right?
what keeps the filter attached to bottom of pump - if that is where it goes?

sorry for the silly questions I am just not familiar with these parts before...
thank you in advance

[Mattchu60]

This is all from memory - I did this around a year ago so its not super fresh anymore.

1- the feeder tube from 381 "butts" against inline with feeder tube from sender? - I believe they almost will touch, its a bear to get the chunk of hose in there, I believe I slipped the hose on the pump first, and then onto the sender.
2- how do the clamps included with the 381 work? - I did not use those clamps, I think they need some special crimping tool. I got Earls EFI hose clamps for mine, but I think that any EFI rated clamp would do (not a standard worm clamp).
3- the "foam" sleeve included with 381 slips over the elect. conn and hose assy. and butts against rubber sleeve on the top of 381 - I remember putting that foam sleeve on the pump, but not sure on the exact spot it sits. I think mine covered most of the pump exterior.
4- the rubber base sleeve fits the 2 tabs on bottom of 381 which pinches between circular base of sender? I dont recall anymore, sorry.
5- the white filter with steel ring slips over the circular bottom portion of 381 - Yes - the filter will friction fit onto the bottom of the pump.

[rodstored-72]

mattchu,
Thank you for the reply... I will redo my clamps.... I will probably go ahead and get the more robust fuel line as well. I mainly wanted to verify that I was "installing" the pump correctly.. as I have no experience in this realm...

thanks!!