I have a 1995 GMC suburban k1500 5.7L. They make a 7.4L motor for this specific truck as well same make and model suburban just different option. I just don't know if the wire harness is different.
You need the wire harness, the ECU, any external sensors, the exhaust, etc. Are you tired yet? This thing is almost 20 years old, why screw with it? The 454 will give you more torque, good if you are pulling a trailer, but not worth the hassle.
More than likely it's different but no need to swap the entire thing, just the parts that are different. Most likely the ignition system and probably the location of the other sensors like oil pressure, water temp and maybe the location of a few other items like alternator and starter.
