98 5.7 vortec swap to LM7 5.3l need wiring help

[shmiet]

I'm having trouble finding exactly what wiring is required for the modified LM7 harness to swap into a 98 sierra with a 5.7 vortec.
I have followed lt1 swap's guide and removed all the emmisions etc. I'm keeping the 98's 4l60e so those wires are staying.

-will I have to make up an obdII connection for the LM7 ecu?
-what other modifications will i have to make to the LM7's wiring harness?
-what can i remove from the 98 vortec wiring harness?
-is there anyway to use the LM7 a/c compressor?

I also need some help with deciding on which water-meth injection to get. It's going to be a turbo-ed engine and it should make about 650hp. I'm not sure how many cc's I should be looking for in a kit. I'm not looking at spending alot on the kit either.



Any help would be greatly appreciated. Thanks

[capricefrk013]

LT1swap.com Plenty of wiring info. Or you can do what I am planning on doing which is using my stock harness to run my LQ4.

[shmiet]

im new to wiring engines, and i do agree its a great site, but i would like some specifics. Im just trying to avoid messing up the wiring harness, and i want to keep things as simple as possible without soldering all new connections etc.

[capricefrk013]

There are a lot of videos on youtube about de-pinning the main plugs for the PCM which will make it a whole lot easier to do the harness swap. Follow the diagrams carefully on LT1swap.com and you cant go wrong.

[shmiet]

I have already de-pinned the harness(as per lt1swap.com), im just wondering if ill need to make up an obdii connection etc, specifically for this swap. It seems that the site is more so geared towards installing the engine in a vehicle that isnt already equipped with a computer etc. An example would be which computer should i have running the fuel pump?(Does it matter?) which should have the Alternator connection?

[Ian Johnston]

I am certainly no expert on this, but will the 98 fuel pump handle the required pressure of the later engine? You may have to run the later pump, which would mean running that off the later computer. I think you will need the obd11 wired to suit the newer engine also, as you will be reading codes from the new engine.