LC9 swap questions

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7mile

Junior Member
Joined
Mar 29, 2024
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Location
Missouri
First Name
Taylor
Truck Year
1982
Truck Model
K10
Engine Size
350
I have a complete, running, bone stock 08 Silverado with a LC9 5.3 that I'm using as a donor truck. All the wiring, computers, fuel tank, etc. And AFM, which needs to go obviously. Probably adding a btr stage 3 cam.
I want to transplant the engine into a 1981 k10 with sm465. Keeping the sm465.

What's the best route to go as far as:

-Tuning (use existing computers? Standalone?)

-Cooling system (LC9 obviously has electric fans in the existing truck, the 81 has a clutch fan)

-Making the gauge cluster work?

I don't need cruise or a/c. Also this is going to be a daily driver.
 

Vbb199

B-rate Hillbilly Customs
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Jan 12, 2018
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Location
Salisbury NC
First Name
Vince
Truck Year
89, 79
Truck Model
89 Suburban R1500, 79 C10
Engine Size
350, 502
Hptuners is the goto for stock pcm tuning. Im sure someone local to you tunes.
If you were local to me, i'd help you tune it myself.

Optionally the holley terminator is great aftermarket solution, as is other systems like fiTech.


Put the E fans in the truck?

Making the gauge cluster work isn't real hard since you're using a manual.

You got oil pressure off the motors sensor, voltage off wherever you want thats key on power, speedometer off the cable on the sm465, rpm signal can be taken off the PCM ... most aftermarket management also has RPM output wires.
Engine coolant can also be taken off of the 5.3 sensor
 

TotalyHucked

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Location
Auburn, Georgia
First Name
Zach
Truck Year
1985
Truck Model
Sierra 1500
Engine Size
5.3
What's the best route to go as far as:

-Tuning (use existing computers? Standalone?) - Definitely use the original computer and get a custom done for it. I have ~36k miles on my 5.3 swap with an OE computer and have had zero issues unlike many of my friends with Holley or god forbid FiTech (do not, I repeat DO NOT even LOOK at FiTech. It is junk beyond comparison). Also, don't go too big on the cam since you're in a heavy 4x4. You want more of a torquey cam than a big choppy cam.

-Cooling system (LC9 obviously has electric fans in the existing truck, the 81 has a clutch fan) - Order a 454 upper radiator mount from LMC and the 4 radiator cushions, then order a Spectra CU730 big block radiator and order the fan shroud from Tejas Steelworks. Then order some SPAL 13" fans off Amazon. Wiring harness from Ron Francis. That exact setup has served me well, sitting dead stopped in traffic for hours on end in the middle of the summer in lower Alabama and never ran over 210*.

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-Making the gauge cluster work? - You can pick up a cluster from a '91 'Burb/K5/30 series that should have the electronic speedo. Or going with Dakota Digital is the easy (though expensive) way. I have Dakotas in mine.

I don't need cruise or a/c. Also this is going to be a daily driver. - You're in Missouri and don't want AC in your daily?? lol
 

Drauka99

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Apr 24, 2023
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70
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140
Location
Northwest Florida, USA
First Name
David
Truck Year
1981
Truck Model
C-10
Engine Size
6.0 LQ4
I have a complete, running, bone stock 08 Silverado with a LC9 5.3 that I'm using as a donor truck. All the wiring, computers, fuel tank, etc. And AFM, which needs to go obviously. Probably adding a btr stage 3 cam.
I want to transplant the engine into a 1981 k10 with sm465. Keeping the sm465.

What's the best route to go as far as:

-Tuning (use existing computers? Standalone?)

-Cooling system (LC9 obviously has electric fans in the existing truck, the 81 has a clutch fan)

-Making the gauge cluster work?

I don't need cruise or a/c. Also this is going to be a daily driver.


Tuning- Send off the existing computer to a reputable tuner to get the AFM and VATS deleted as well as setting it up for the SM465.

Cooling system - a few brackets and the bottom of the radiator support from the donner and you can hook up the existing cooling system including all the hoses, fans, expansion tank and radiator.

Gauge cluster - I used the spare coolant port on the passenger side head of the LS for an adapter and a stock C10 sensor. Also added a thread adapter and stock c-10 oil sensor to the oil cooler connection on the oil pan for oil pressure.

I did run a holly knockoff shallow oil pan on my swap. the mid-shallow oil pan works fine, don't need the one where you have to cut the windage tray. Stock truck pan fits but the sump sits lower than the k-member and that worried me on bumps and such in my area.

SM465- I went stock C10 clutch, throwout bearing and pressure plate, went with an 01 Silverado flywheel.

Drive by cable you can use the early 2000s cable to connect to the stock c-10 gas pedal. If drive by wire then you can mod the existing donner pedal to make it fit or I used a 99 GM truck oil burner, it bolts right in the c-10 space and fits the footwell right, just have to swap 2 pins on the harness

I used motor mount adapters from ICT Billet as well as some other items from them for my swap.
 

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