I would first ask why you would want to swap it out? there are some aluminum 5.3s in the newer vehicles. I believe your old engine would be a gen III engine while the newer one would be a gen IV. this means that the injection system would be a returnless one, the knock sensors might be on the side of the block like ls2s instead of under the intake, it could have lifters for VVT and could utilize active fuel management , front mounted cam sensor, and 58x reluctor wheel. Now please realize that this info is only known by me because i changed to a GEN iV in my tahoe a few years back and these were things I had to deal with. i re-wired my knock sensors, and my cam sensor (which requires switching wires and a tune) I believe you can tell if your new engine is 58x or 24x by the color of the sensor. ummmmm grey means 58 and black is 24 possably. I only remember that from someone elses post. If i was you i would look up information on swaping from a gen3 to a gen 4 i wish I could help more, but I did it a long time ago and i go not have my schematics for wiring up the sensors and sutch. good luck, if you have more questions just ask