If you have to rebuild your engine, why all the hate against trying to bump the HP a bit?
Picking up someone elses 4.0L seems like a gamble to me, you don't know its history. Stuffing another engine in it seems like a headache, your still left with someone elses engine plus everything behind it might not be up to it.
I have plans to stroke my 4.0L in the future as well, refresh it and get a little more out of it. I hope thread gets back on track....