Here take a peak at this page... should tell you everything you want to know about the swap....
Converting the TJ / LJ Jeep Wranglers to GM Engines
The 5.3L in 04 pumped out 295HP and 335 TQ.
The 5.7L hemi motor pumps out 345 HP and 375 TQ.
Your stock motor is the basic same motor in the Neon and is known as a Neon Variant motor... 150HP and 165 TQ
The Stock Transmission for the Chevy/GMC is the 4L60E in early years the 4L65E in later years and the 4L80E in the heavy duty tow option.
If you need any photos of how they look in the Stock GM trucks let me know, I think we have an 08 all apart at work. I can get you photos you would never get to see anyplace else. Oh if anyone needs photos of the Transmission and transfer case in the Dodge PU with the hemi let me know. I rip them apart weekly.