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75 K5 Build thread

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75K5

1/2 ton status
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75K5 submitted a new Build:

75 K5 Build thread

OK, the swap is underway. I have removed the GM 305 carburated motor, transmission, and NP203.

The new engine is a 5.3 LMG from a 2009 tahoe that was wrecked with 900 miles on it. It was 2WD and I didn't want to swap the tailshaft in the 2WD 4L60e transmission to a 4WD version so I picked up a 2007 4L60E 4WD transmission. I also picked up an 88 NP241 with a mechanical speedo.

Right now I am re-wiring the harness and buying a VSS adapter to install a VSS between the transmission and transfer se so it shifts properly in 4WD-LOW. Turns out if you use the VSS in the transfer case the transmission will not shift properly in 4-low unless you have a 4WD ECU and can set the 4WD switch in the ECU while shifting to 4-low. It's not that simple with 07 and newer ECUs that require a bus signal to activate 4-low.

Using the stock VSS between the trans/transfer case with a reluctor ring also makes rewiring simple. I just have to clean up the harness, extend it so it can mount cleaner, and wire everything up to use the 09 tahoe factory fuse box. I plan to keep most of the GM sensors, electric fans, and active fuel management. I'll use HP Tuners or EFI live to tune the engine when the time comes.

After the wiring, I need to figure out the fuel system and NP241 shifter. Then I'll be ready to install it. I picked up some engine mounts on eBAY that claim to fit the stock crossmember and also clear truck truck manifolds. Hopefully this raises it up enough to give me good clearance.

I also picked up a LS1 "PHAB" turbo kit. When I test fit the engine I'll see how well the headers fit. I already figured I'll have to make a new cross over pipe. I also want to incorprate catalytic converters in the crossover pipe. I still have to figure out correct turbo to spool quickly, but there's plenty of time for that.

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Read more about this build here...
 
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Sounds like you got a good plan,that will for sure be a nice combo when you are done with it. Turbo aswell NICE!

:popcorn:
 
made some more progress, slowly. I am keeping the fusebox from the 09 tahoe so I have extended the wiring harness to clean things up.

Because I am using an 09 Engine and wiring harness and a 07 transmission, I learned the hard way that the transmission changed in 09. I had to add 4 pins to my TCM and four extra wires for the 07 transmission. Apparently they deleted some wires in 09, but I plan to run an 07 TCM calibration.

I should be getting close to test fitment.

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Man that's a lot of spaghetti. I'm still not ready to tackle this kind of swap. But i'll watch you do it...:popcorn:
 
the forward facing header is a part of the phab turbo kit. The cross-over is in the front. Once I fit the motor we'll see if it's going to work. The hot pipes were only $350 so I'll just sell them and do something else if they require too much modification.

Today I ordered a few things. I ordered a 31 gallon fuel tank, sending unit, sanden SD5H14 compressor, and kwik AC relocation bracket. I still need to figure out what fuel filter to get, fittings from the tank to fuel line, and a few other minor things fuel system related. I think I have the AC system covered and I plan to have that controlled outside of the ECM.

I also got these engine mounts, I'm interested to see how they fit:

http://cgi.ebay.com/ebaymotors/ws/e...0562152999&viewitem=&sspagename=STRK:MEWNX:IT



Brian
 
I am plannig to delete this bracket. It was under the blazer and I think it served as some type of protection for the old transfer case. Chris, did you have one of these in our 75 K5? Did you keep or delete it?

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Here is a pic of the trans cross member. Chris, what did you use for the mounts? Just the stock mount? Below the mount is a pic of the mount that I pulled out of the 09 tahoe, doesn't look like it will fit.

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I tried to attach all of my wiring diagrams, but it won't let me attach an excel file. Any idea how I can get around that? I have basically retained the engine harness as-is. I had to add 5 pins to the TCM because I am using an 07 4WD transmission with an 09 harness. The 09 harness did not have a brake switch pinned out, and the 09 trasmission internally changed and had less wires running to it.

This is still a work in progress
 
75K5 said:
Here is a pic of the trans cross member. Chris, what did you use for the mounts? Just the stock mount? Below the mount is a pic of the mount that I pulled out of the 09 tahoe, doesn't look like it will fit.
Click to expand...

I used a crossmember out of a later model K-5, SUB,TRUCK etc, that had a 241. I just had to drill 2 holes and the rest of them lined up. That allowed me to use the stock mount.
 
thanks for the info. How different was the newer style mount? I'm wondering if I can just drill holes on my old 75 mount. Do you have any pics?
 
They are very different. Best to hunt down the one that works.
While your at it get the [bolt-in not welded] doghouse center section of the floor board.
It's slightly longer than your 75 one is but, with a little cutting it will fit. Do this so that your t-case linkage will bolt up nicely too.
The floorboards changed over the years.
 
Yeah, I never saw this thread last year, I am interested as well.

Martin
 
it's been a long time! The K5 is up and running with the 5.3. Turbo is not on it right now, I want to debug everything N/A first and really get it running right. So for now I am running the stock manifolds and cats. When I am really happy that it's running right and all the kinks are worked out I may boost it. I will take some pics in a week or so.

I used the stock trans crossmember, but that left the transmission too high and I am chasing down some driveline vibration that I think is related to driveshaft angle. I am going to try some different trans crosmembers and see if I can find one to drop the tranmission a couple inches.

Chris, is this the one you used?

Brian

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More pics :D. 5.3 swaps are cool. I may try it on a vehicle later on down the road.
 
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