What I need to know before LS1 swap K10

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broke78

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Jan 27, 2024
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Location
Klamath Falls
First Name
Matthew
Truck Year
1978
Truck Model
K10
Engine Size
400
Hey friends,

I'm new to the forum and to owning a squarebody (78 K10). Despite my lack of experience, I hold the achievement of grenading a smallblock. I intend to rebuild it in the coming years as built 400s aren't common and have a lot of fun potential. In the meantime, I want to get the truck running (weekend cruiser/soft daily driver) because the car I'm being loaned is running with a dying turbo (no idea how long it has). While there are cheaper and easier swaps, I have found a handful of LS1s dropped from running C5s with proof of them running and leak down tests provided. At $3800 OBO they include most accessories (starter, all belt-driven, donor harness+ecu), which seems like a decent deal for an engine I want/need to run for at least 5 years. I've found mounts and flex plate/adapter kits for about $150 combined, and clean exhaust manifolds will run another $300. I'll have the stock th350 to np205 behind it, and from what I've read the new flex plate should bolt up perfectly and the drivetrain should hold as long as I'm not treating hwy97 like an nhra strip. I intend to swap transmissions at some point, but if I can get it running now, that's how it'll stay for the near future. Wiring will be a pain, and reinforcement and fitting where it'll sit will be worthwhile if not necessary. I can find pictures of people who have swapped LS1s, but rarely with keeping as much stock as I intend to. I know with enough time and effort you can ls swap anything, but I want to get it right. What all am I missing to make it happen, and what issues can I expect to encounter?

Thank you,
Matt
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disenough

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Location
Rock Hill SC
First Name
brice
Truck Year
1986
Truck Model
k10
Engine Size
350
I did an LS swap in an 89 K10 suburban.
I mostly followed a guy on youtube called The ugly truck experience.
I used the stock manifolds.
 

Nasty-LSX

TogetherforeverCovid19
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Location
HOUSTON TX
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Mi Hung Lo
Truck Year
85/86/87
Truck Model
c10/k10/k20
Engine Size
LSX
I have full build on mine if your interested. You need to go to my channel and click videos
then find all the c10 build stuff. Should help you with yours. I went a different route with the
gas tank but everything else is common swap stuff.


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Drauka99

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Location
Northwest Florida, USA
First Name
David
Truck Year
1981
Truck Model
C-10
Engine Size
6.0 LQ4
I did an LS swap in an 89 K10 suburban.
I mostly followed a guy on youtube called The ugly truck experience.
I used the stock manifolds.

That's who I followed. LT1Swap did my computer work (after I tried local and he failed) I used a few different parts the Ugly Truck. I didn't use Holly for the fuel pump (to expensive) And I found some rubber spacers for under the LS radiator support rather than the metal he uses, I figure more vibration reduction can't be a bad thing.

Main things I recommend, use a reputable source for the engine mount adapters, i used the SBC to LS ones from ICT Billet, not the plates the full kit and mine went super easy. My LS is drive by wire, I used the 99 diesel pedal and a conversion harness from PSI. The pedal on drive by wire is a sticking point for a lot of builds it seems. If I had to do it again I would seriously consider going to a drive by cable throttle body.
 
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hoagster

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California
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Mike
Truck Year
1973, 2000
Truck Model
K10, 1500
Engine Size
5.3l
Welcome from Redding CA. All the sites mentioned above are good idea's and keep searching on this site because there is loads of info here. I'm going to add another because there it also has a lot of info that you can use i.e. fuel connections and cooling info. bdturnkeyengines.com
There are some downloadable documents that can help with all the required and non required wires on the ls engine harness. at lt1swap.com

Enjoy
 

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