The life of a Magnum (and 46RE question)
The early 4.7's had a boat load of issues from filling crank case with white oil foam to snapping cams. They did get better and put out more power later on. The trans was no gem either.
The 5.2 is underrated in many places, FSM has 240 listed in many places, some data and mitchell list as 190-210 but also list 4.0L as 195 so who knows. The 5.2 was typically 235-245 HP and was capable of 20 mpg in 4x4 Daks with NV3500 trans. Had one, also had a 4.7 CC Dak that was shamefull.
5.7 are a whole other bag o worms....already coined "hemi tick" and some other interesting lower end issues.
Consider the cost/issues with 5.7, it just makes the 5.2/5.9 an easy choice, plus they are almost free and $1500 will make more than 5.7 HP . Having one of the best production short blocks helps too.