I have a 2004 Chevy Chevrolet Silverado I would like to know what a 2013 Chevy Silverado motor with aluminum heads work in my 2004 if I change my wire harness as well
It's possible but it's going to cost your A LOT of money and time. Like what was already mentioned, a lot of the electronics are different (the sensors, harnesses, pigtails, knock sensors on the engine, the computer itself, so much more). What is wrong with your current engine? You could always go find an LQ4 (earlier 6.0 liter) from the junkyard and have a performance shop re-tune your truck. Are you after performance? There are a lot of options in this arena, such as a turbo kit, or supercharger kit, that can be had for very cheap.
Basically, yes you can install the 2013 engine into your 2004 Silverado, but there is more to it than just the engine, wiring harness, and computer. Both engines are Gen III/IV LSx based engines. The Silverado didn't receive the LT1 engine until 2014. The 2013 will most likely have Active Fuel Management (aka: displacement on demand) as well as variable valve timing. Your 2004 will have neither. The 2013 will also be drive by wire (the computer controls the throttle body) instead of your drive by cable (throttle cable controls directly from the foot pedal). There are plenty of other differences as well.
Basically, you'll need to tear out the entire thing, which I'd include the transmission and transfer (if so equipped) and make it a complete swap. If you do a complete swap, not only will you get a better end result, but it'll last longer in the end. The 4L60e in your 2004 (assuming you have a 1500 non-HD version) is the weak link in the drivetrain. The 2013 would most likely have a 6L80e six speed, depending on the engine. If you go this route, you'd need to do some fabricating to mount the transmission/transfer as well as need to get some new driveshafts.
If you go the engine alone route, it will bolt directly to your transmission and motor mounts. You'd still need the engine (oil pan to throttle body ... IOW: complete pull out including accessories), wiring harness, computer, & gas pedal assembly. If you can find a complete donor vehicle, this is the best way to go, as it would have all the parts you'll need to do the swap. Your computer will not work with this engine as there are too many variables (Note: Will not work without MAJOR work, time, & money).
It's not an easy task, but it can be done. You'll have to put some research and work into how to get it done, but it would probably be worth it in the end.