Since that Mountaineer has the coveted GT-40p heads and the Explorer intake (very similar to the Cobra), I would stick a different cam in there and some forged HO pistons. A little exhaust work and voila, 320hp.
You should have AWD, not 4WD, which will be killer in snow. I'm not familiar with any real problems on those trucks, but then again, I haven't really looked into them.
Killer vehicles though!