Re: Engine swap
4.2 crank+rods won't necessarily gain you anything. Remember this: power is made in the head. With the intake and exhaust on the same side with the 4.0, you really can't gain a ton with the airflow having to make a 180deg turn right out of the combustion chamber. Not unless you consider boost, which is a whole 'nother conversation that I don't feel like getting into.
Sell it and buy an Overland if you want big power gains. For $6000(or less), you'll be much better off. The 4.7 is honestly a powerhouse with the right mods, and starting with a H.O. is 80% of the way there. Not to mention you'll acutaly get better real world mileage, driveability, and sound. My '99 non-H.O. can rock out on 75% of the crap out there off the line, and I honestly can't find much to mess with since I put an exhaust on it.
The Brown Trout[SOLD]
On the hunt for a 5.9 or 4.7 HO Limited...
In the meantime, this is pretty entertaining....