EFI Swap...I need advice

[DirtySouthK10]

So I've recently decided to EFI swap my 1979 K10. I am running an Edelbrock 600 carburetor currently, but ive been doing some research and I really like the EFI system that Holley is offering. However, i am running OEM dual tanks...and i dont want to use the single fuel pump offered in the kit and plumb it in after the selector valve...i feel that its a LOT of strain on the fuel pump. Should I just run 2 fuel pumps? Holley looks like it has a replacement selector valve with built in dual fuel pumps...i just dont know what to do. I have 5 months before im back from deployment and I want to have a solid plan so I can start my swap asap when i get home. Any and all help would be greatly appreciated, thank you!

 

[bluex]

The Sniper requires 58 psi just like an LS. You can follow the plan that those guys use to keep dual tanks when they LS swap. I'm not sure of all of the details for that but for my Sniper I used an 87 model tank and sending unit with a 1996 C1500 5.7l fuel pump. It works great an I spent about the same as the master kit. So you would just do that for both tanks an maybe a new valve an wiring for the fuel pumps. I know 87 was a special year for the valve an selector switch wiring as that was the only one that had in tank pumps.

As an alternative you could always swap to a K5 tank in 25 or 31 gals. But that has it's own challenges as well.

 

[Charlie]

 

[DirtySouthK10]

Blue, thank you. I did continue some more research...i think your idea about switching to a single tank would be ideal. I believe there is a 25 gallon that goes where my spare tire should be. Im going to look into that option in depth. Thank you for your input! As for the rest of the swap, ill just need to find the right "how to" instructions for my 5.7

 

[bluex]

Putting the Sniper in is fairly straight forward. Just pay attention to your wire routing, make good connections, and read the books about 4 times! There is also a tuning manual that goes into deeper details than the one that comes with it. You have to download it from the holley website.

 

[TerColHan]

Blue, thank you. I did continue some more research...i think your idea about switching to a single tank would be ideal. I believe there is a 25 gallon that goes where my spare tire should be. Im going to look into that option in depth. Thank you for your input! As for the rest of the swap, ill just need to find the right "how to" instructions for my 5.7

The tank in my 91 Suburban is set up for fuel injection and 31 gallons and there's also one that's 40 gallons. It also sits between the frame rail where your spare would be.
TPI doesn't require the same presure as the Sniper so you'll need to upgrade the in ank pumps but you can get a walbro in tank 255 lph pump for about $50 on ebay that will mount in the factory sender. The Sniper has a built in regulator but you'll still want to add a in-line filter ahead of the Sniper.

 

[yevgenievich]

40 gallon suburban tank does not fit behind the axle unless on a long bed

 

[4WDKC]

The Sniper requires 58 psi just like an LS. You can follow the plan that those guys use to keep dual tanks when they LS swap. I'm not sure of all of the details for that but for my Sniper I used an 87 model tank and sending unit with a 1996 C1500 5.7l fuel pump. It works great an I spent about the same as the master kit. So you would just do that for both tanks an maybe a new valve an wiring for the fuel pumps. I know 87 was a special year for the valve an selector switch wiring as that was the only one that had in tank pumps.

As an alternative you could always swap to a K5 tank in 25 or 31 gals. But that has it's own challenges as well.

if this is true then you can use the 96-99 vortec pumps (ep381) for the sniper as those pumps are rated for stock ls engines. Oh and it fits in the efi hangar for our trucks with no mods.

 

[bluex]

if this is true then you can use the 96-99 vortec pumps (ep381) for the sniper as those pumps are rated for stock ls engines. Oh and it fits in the efi hangar for our trucks with no mods.

It is true, the EP381 pump has been running the sniper on my truck for over a year an 6k miles now. That's exactly what I did, 87 baffled tank, 87 sending unit and the EP381

 

[TerColHan]

The EP381 is a 190LPH pump, good to a little over 300HP and fine for most stock applications but can pretty quickly become marginal at best with further engine mods.
I used the 255LPH pump on the fuel injection conversions I have done for my 84 Hurst Olds and the one I bought for the Sniper conversion I'm doiing on my Suburban (once Comp finally ships my new cam kit). That pump is good to about 550HP which should be fine with the low compression gen 6 motor in my truck now, even with the cam swap.

This article highlights the differences in flow vs pressure..

http://www.gmtuners.com/tech/fuel_pumps.htm

 

[Frankenchevy]

The EP381 is a 190LPH pump, good to a little over 300HP and fine for most stock applications but can pretty quickly become marginal at best with further engine mods.
I used the 255LPH pump on the fuel injection conversions I have done for my 84 Hurst Olds and the one I bought for the Sniper conversion I'm doiing on my Suburban (once Comp finally ships my new cam kit). That pump is good to about 550HP which should be fine with the low compression gen 6 motor in my truck now, even with the cam swap.

This article highlights the differences in flow vs pressure..

http://www.gmtuners.com/tech/fuel_pumps.htm

That article puts the ep381 at 381 hp normally aspirated. 300 hp with forced air induction.

I got the ep381, but will explore other options if I upgrade the engine past stock, based on that article.

 

[Dan Brown]

I'm currently doing the same thing to my (actually my grandson's) 1974 K10. I've adapted a Throttle Body injection off a 1995 Chevy pick-up to the 350 (actually 355). Instead of buying an adapter to make it fit the manifold, I made one out of 1/4 inch think Aluminum plate. I, too, built my own wiring harness instead of paying somebody 300 to 400 bucks for one. Have all the necessary sensors to make it work. What I did with the fuel tanks and pumps is, instead of using an inline pump, I adapted two pumps to the existing pick-ups in the tank, so I now have in the tank pumps. Had use a trick switch to make it all work, i. e., to switch tanks, pumps, and gauge reading. Much cheaper than an off the shelf EFI unit.

 

[ironhead38]

I have the ep381 in my 85 with 87 tank with a 383 with 500 hp works great no problem with enough fuel. Been on chassis dyno with a good tuner he said it was fine.

 

[Kasey 1977 K10]

I recently just completed this for my 77' K10 with dual tanks. Take a look at https://www.gmsquarebody.com/threads/tank-replacement-for-efi.24131/page-2#post-472294

 

[asltrfl]

Don't forget the filler tube if going to a single tank, a pain in the ass if you don't get the burp tube in correctly. I prefer a clean running carb motor, with mechanical fuel pump under the hood, 30 minutes to change it out. A well tuned quadrajet is the best, but Holley or Edlebrock if your willing to learn everything about how they work. Bigger cam, and old school high rise and headers. Hell, it's a truck, not a Camaro. You can fix / adjust most anything it will throw at you on the side of a dirt road. I get it, most of my trucks are F.I., and I have to use a scanner when they throw a code. I know it's really not that complicated for those of us with experience, but it also takes me 8 hours to change out a in tank fuel pump and two days for my muscles to recover. But if your not in a emissions inspection zone I like to keep it simple, clean, and module free.