An '02 500 EFI power package should have the XZ. I have the "X" (which is the same top half as "xz", just with the improved DWP standard bravo lower) 0n my early '02 496 HO boat. Did you check numbers on the build sheet or other time-of-build references? Is this a small builder or large? Does it have the HP gimbal? This may be an engine and drive that were not originally packaged together by Merc, or an older model year (than the '02 boat) engine/drive package. This is worth looking into for bargaining (on price or drive) purposes!