Dirtyrat
Got Fins?
I have swapped body harnesses in Escalades and Caddy Devilles (up to the 2010's) and they look like a mess. Once you blow apart the engine harness it will look intimidating too! I suggest doing a nail board on a piece of ply wood. Then you can clamp each connector to a nail in the postion you want to ruyn it. Then it is just a matter of lengthening and shortening the wires to match. You can take a ton of wires out as well. The worst one I did was combining a 2004 6.0L chevy motor harness with a 1999 mustang AND kept all the gauges, ABS a/c etc. oh and it was turbo charged to boot! it also looked factory when we were done. About 40 hours into it though!
I've done a few as well, probably one of the least fun portions, but one of the most rewarding when you can take the time to re-route wiring and get most of it out of sight, I was planning on running the harness under the runners of the intake if I can and also hide a lot of the electronic stuff under a large-ish intake scoop I'm going to make out of an old tractor hood...