Seems a little excessive, unless guy was up front with him like "hey I'm busy so it'll take a while"
And I'm not everyone else but LS to OBS plug and play harness depending on diferent variables takes around 20-25 hrs with possibility of up to 30 depending on what you loom it with, changing of routing, etc
That time was based off taking a vortec 350 4x4 harness and stripping it of everything not needed
Also a 03+ LS harness stripping it then converting it back to 99-02, removing DBW wiring and took IAC, TPS wiring from the stock 350 harness and added to the ls harness
Then after making the 2 into 1
Also was experimenting with this one so a few things weren't loomed until we got it into the truck
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but to me sounds like dude yanking you around a bit