RE: 98 5.2 magnum hp?
I believe you are correct.
I believe from 1992-1994, the 5.2L made 230 hp. In 1995 and onward, they did something that subtracted 10 hp but added 20 ft lbs or so of torque. The 5.9L up until some year (not sure exactly when) made 245 hp, but during one of its last years (sometime around 1999, I think), they did something to it to get an extra five.
Someone with more experience: feel free to elaborate or correct me on the numbers for the 5.9L.
As far as rear wheel HP, I'm not sure. Someone else here has the numbers, I'm sure.