Considering the dealer is getting a long block and will need to strip the engine, remove it, move everything over, reinstall, rewire, replumb, startup and test, I'm not so sure 15-17 hours is enough. When I was racing it certainly took me more than that, but, then again, I was not trying to make a living at it and certainly was not rushing.
I would certainly be pissed if I had just bought a 70K - 90K new truck and then have to have it all torn apart, I guess better than having the engine fail 600 mile from home towing a trailer.