99 K2500 OBS lq4 swap

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07-28-2016, 11:31 PM
Greenchevelless

99 K2500 OBS lq4 swap

So ive got an Lq4/4l80e out of a 2wd 2500 van that was totaled. I ended up getting all the wiring and accessories but probably wont be using the van stuff.
The truck is a 99 or 00 Model K2500 that has the l31 5.7l vortec with 4l80e trans.
I plan on using this truck almost everyday and towing with it on occasion. The only reason Im doing this swap is the 5.7l is toast and i came across the lq4 pretty cheap. I would not 5.3 or 4.8 swap it.
So my question is what all is involved in swapping with the wiring, computer and gauges? I will need engine adapter plates and planning on getting a set of shorty headers. I will be using the 4l80e thats in the truck since its good and already 4wd.
I have all the accessories, wiring, manifolds, oil pan, ect from 4wd 5.3s that i will be using for the swap instead of the van stuff.
07-29-2016, 06:38 AM
1991SSP

You should be able to leave the stock 5.7 harness in place if you understand the wiring aspect.. I recently put a 4.8 into a 96 K1500 ,, re pinned the PCM, on the engine side it's not too big of a deal,, extend some wires and add a few connectors, ECT, Fuel Injectors, add some wires for the coil packs. etc....
08-01-2016, 11:11 AM
hokeplaya05

look up lextech on here, he has the pinout sheet to convert (re-pin) your factory 5.7 harness over to the run the lq4 and you can run the 411 computer from the van too.
08-01-2016, 08:10 PM
1991SSP

Quote:

Originally Posted by hokeplaya05

look up lextech on here, he has the pinout sheet to convert (re-pin) your factory 5.7 harness over to the run the lq4 and you can run the 411 computer from the van too.

That's where I got my info from... his information is A+
08-13-2016, 11:10 PM
Greenchevelless

Well I got the adapter plates ordered Im gonna try and use the pacesetter headers. Been working on the interior of the truck first to get it cleaned up then im gonna pull the front clip and yank the 350 out. Im gonna try and use the LS ac compressor, we will see how that goes ive seen a couple of people do it and Ive got some ideas so its just a matter of how much work I want to put into it.
09-20-2016, 09:28 AM
Ray@NP

Quote:

Originally Posted by Greenchevelless

Well I got the adapter plates ordered Im gonna try and use the pacesetter headers. Been working on the interior of the truck first to get it cleaned up then im gonna pull the front clip and yank the 350 out. Im gonna try and use the LS ac compressor, we will see how that goes ive seen a couple of people do it and Ive got some ideas so its just a matter of how much work I want to put into it.

we have used the stock A/C compressor on obs before, its not too hard to do. We just notched the frame and boxed it in, there is still plenty of room to replace compressor if needed.