4.7 V8 swap?

It would be fun. Those things go like scat. They aren't much bigger than a 273 (.030 bigger bore and a little longer stroke) and perform about the same:
The 05's were rated at 235 hp. and 295 ft.lb. (HP273's were 235 hp and 280 ft/lb)
The 08's were rated at 290 hp. and 320 ft.lb. depending on model
A 08' Ram was rated @ 310 hp. and 329 ft.lb.

Build yourself a nice HP 273 with some lightly ported heads and get 300+
hp and torque. Here's some interesting reading:

http://www.allpar.com/mopar/47.html