Ls swap question

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Timmy adkins

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I’m swapping a 5.3 into a 79 c10. The swap/wiring isn’t an issue on this one. I’m just wondering how you guys have gone about fueling options on your swaps. I know you can get kits and all that. My question is this. I’ve got a complete 99 Silverado with a bent frame that is responsible for donating every part I need on this swap. Engine, harness, computer, etc etc. is it possible to take the tank from the 99 and install it on the 79 frame. Right in the place of the original one? Has this been done? That way I could use all the fuel lines from the donor truck and all that.

the float for the gauge on the 99 should be 0-90ohms. Same as the 79. So theoretically that should work. Right? Idk maybe I’m getting into more work than I need to but it seems possible.

The inline pumps are noisy and I don’t want to sink a bunch of money into a in tank pump kit. I’ve seen people splice pumps onto the stock senders but the location of the float prevents me from doing this and maintain the proper depth for the pickup.

I’m trying to rob every single part of this donor I can.
 

eskimomann209

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The float must be spliced on to the 87+ fuel pump and tank. I haven’t heard or seen anyone use the tank from the nbs trucks. But I used their fuel lines and filter. Above the gas tank on the nbs truck is some plastic lines. I cut there and made a connection to the top of the squares tank using earl braided lines and compression to -6an connectors. I have seen someone wash out both tanks real good cut the fuel pump mount off the top of the nbs tank weld it onto the Squarebody tank. But you gotta add baffles around the pump and make sure your depth is correct. We used a tig welder and purged the tank.
 

Timmy adkins

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The float must be spliced on to the 87+ fuel pump and tank. I haven’t hear or seen anyone use the tank from the nbs trucks. But I used they’re fuel lines and filter. Above the gas tank on the nbs truck is some plastic lines. I cut there and made a connection to the top of the tank using earl braided lines and compression to -6an connectors

Ok. Im trying to use every part from the rails back. The pigtail that comes off the 99 sender has four wires. One of them is for the gauge. My theory is that if you take the wire from the original gauge and tap it in there, it should work the gauge properly. Being that the ohm range is 0-90.. so the old gauge would essentially operate just as the 99 gauge would because the float matches that tank. Then I use all the lines and filter from the tank up to the rails without having to get any additional parts.


Correction. The donor truck is an 03.



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eskimomann209

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Ok. Im trying to use every part from the rails back. The pigtail that comes off the 99 sender has four wires. One of them is for the gauge. My theory is that if you take the wire from the original gauge and tap it in there, it should work the gauge properly. Being that the ohm range is 0-90.. so the old gauge would essentially operate just as the 99 gauge would because the float matches that tank. Then I use all the lines and filter from the tank up to the rails without having to get any additional parts.


Correction. The donor truck is an 03.



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yeah the ohms are the same for most of not all GM vehicles.
You’ll have ground, relay, signal to fuel gauge. I think the fourth is for the low fuel light or some secondary signal. Shouldn’t need it. I think we capped it off orange with black tracer if I remember correctly. I wouldn’t use the nbs tank I’d do the weld thing if I was you. Avoid some janky fuel necks and mounting. But it’s your truck.
 

Poppy 87

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That 03 fuel tank mounts inside the frame rail. The square body tank mounts outside. I'd buy and 87 tank and sending unit, install your pump and go! New tanks and sending units are relatively inexpensive
 

Timmy adkins

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That 03 fuel tank mounts inside the frame rail. The square body tank mounts outside. I'd buy and 87 tank and sending unit, install your pump and go! New tanks and sending units are relatively inexpensive

The 87 sending unit has a spot for the pump? Which pump should I use for that?


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RoryH19

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Would do the same. Buy the 87 fuel tank (long or short bed version) and the sender without the pump. TBI's need less fuel pressure than the LS. I would also install a new fuel pump. A lot of work to drop the tank again if it goes out.
Assuming you will have a hard line for supply and one for return?
You may be able to use your donor's lines and just make the turns with braided hose and 6AN fittings. Essentially the same thing I did but mine is a return less system.
 

Timmy adkins

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Would do the same. Buy the 87 fuel tank (long or short bed version) and the sender without the pump. TBI's need less fuel pressure than the LS. I would also install a new fuel pump. A lot of work to drop the tank again if it goes out.
Assuming you will have a hard line for supply and one for return?
You may be able to use your donor's lines and just make the turns with braided hose and 6AN fittings. Essentially the same thing I did but mine is a return less system.

I have a bare frame right now. All the lines are still connected to it from the original truck. Should I leave these lines and tap into the fuel rail that way or use the lines off the donor?


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RoryH19

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For the fuel pump I used (9-201-1000) DeatschWerks
Works great and quiet.
You should be able to as long as they are in good shape.
Donors will work as well. Just have to make sure you have the proper bends to connect the fuel pump to fuel rail of the engine.
Does your engine have the fuel regulator built onto the rail?
 

Timmy adkins

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For the fuel pump I used (9-201-1000) DeatschWerks
Works great and quiet.
You should be able to as long as they are in good shape.
Donors will work as well. Just have to make sure you have the proper bends to connect the fuel pump to fuel rail of the engine.
Does your engine have the fuel regulator built onto the rail?

I’m not sure. I’m going to have to go look. But if it doesn’t then I have to get the regulator that goes inline, correct?


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RoryH19

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If you need a regulator you can use the vette style.
It has both a regulator and a filter built in.
Common item used for LS swaps.
 

eskimomann209

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His will have the regulator on the rail. It’s from a truck.
I used all the nbs fuel lines. Just used the braided lines to connect from the end of the lines to the top of the fuel pump

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Timmy adkins

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I need those sending unit right? From the looks of it, there is a pump basin for a fuel pump.


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RoryH19

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I need those sending unit right? From the looks of it, there is a pump basin for a fuel pump.


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Yes that looks correct.
The fuel pump will sit on the base.
I used DeatschWerks (9-201-1000), works well and quite.
You will need to supply power and ground to the pump. The current wire for the fuel gauge can be reused.
 

Timmy adkins

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5.3
Yes that looks correct.
The fuel pump will sit on the base.
I used DeatschWerks (9-201-1000), works well and quite.
You will need to supply power and ground to the pump. The current wire for the fuel gauge can be reused.

Outstanding. I just ordered a new tank and sending unit. Going to order the pump next week...

Not to derail, but when I swap the motor, ecu and harness out of the donor, do I need to get the ecu flashed to get rid of the anti theft system?


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