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Old 12-14-2018, 10:04 AM   #1
Mattchu60
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Join Date: Jan 2014
Location: Swaledale, IA
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LS Swap with Dual Tanks - need some help

I have read and read on how to do a LS Swap with Dual tanks in my 73-87. I have the 87 16 gallons tanks with the EP381 pumps in TBI senders. I'm planning to use the pollak switch valve that handles 65 psi.

The biggest problem I am running into is how to connect all of this stuff. I was going to just run rubber FI hose for everything. But when I started reading other posts, every says to avoid rubber hoses unless its just short runs - main issues is that it could leak and cause a fire.

I need another option to make this work. I have seen where people are cutting off the senders flares and using compression AN Fittings and running AN line. But that would not allow me to connect to the switch valve, which is pre-formed to only accept rubber hose (I'm going to need to use some rubber hose there, no choice).

I wish there was another option. Honestly regretting going dual tanks now and wish I had just done a single rear tank and cut a filler hole in my bed floor - but its too late for that now.

Any ideas or solutions would be appreciated. If someone has done this before I would love to know how you did it.
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Old 12-28-2018, 06:22 PM   #2
fuel injected
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Re: LS Swap with Dual Tanks - need some help

i too have an 87. the p.o. took one of the tanks off for whatever reason. i would love to run the saddle setup but cant find all the info i need to fully travel down that road. i hope a few guys with more knowledge will reply to your question. ill be on the sideline watching....
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Old 12-28-2018, 08:39 PM   #3
cdub2010
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Join Date: Apr 2014
Location: detroit mi
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Re: LS Swap with Dual Tanks - need some help

In my 77 gmc 5.3 swap Im using SAE30R rubber hose from the pass side tank sending unit to my wix filter and Russell AN fittings with ptfe line to the intake from there. No issues with leaks or bursts. I was going to use the pollack valve but mine was broken by an over zealous helper. I might just turn my drivers side tank into a transfer tank with the existing tbi pump.

If I ever get time I going to head over to Inline tube, they mention custom fuel injection hoses with many different fittings. Being local might just be worth it.
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Old 12-28-2018, 11:05 PM   #4
kipps
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Join Date: Jul 2014
Location: North-central Virginia
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Re: LS Swap with Dual Tanks - need some help

I'm working on a complete custom wiring harness on my swap. For now, I'll stick with one tank, but I'm wiring it for a future second tank using the method below.

The dead simplest method of doing dual tanks on a ls swap is also the best for redundancy. Each tank has it's own ep381 pump, corvette filter/regulator, return line, and feeds into it's own check valve. Both check valves tee together and connect to the fuel rail. Either pump can pressurize the fuel rail, and no single failure can leave you stranded.

Install a double-pole double-throw rocker switch in the dash. One side of the switch is simply switching the fuel gauge between the tanks. The other side is switching the ECM fuel pump signal between the two fuel pump relays. Again, if either relay fails, you can switch to the other tank and keep going. The only shared components are the wire from the ECM, and the switch itself.

The disadvantage of this, is that the factory wiring will not match up at all. Everything fuel pump related would need to be wired new.
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