yeah, you'd be up against a serious wall with tuning.
it's really not THAT bad of a swap, but it's no Cummins...
I like 6.0's. They're easy swaps. I'd really like to have a 6.0 Bronco.
but I'm going to hold onto my eternal pipe dream 6.4 swap project because I just friggin' love them, and it's a big enough project that I'll probably never tackle it
(hasn't stopped me from accumulating a couple key pieces here and there)
6.7 would be tits. and they're cheaper/easier to find, but they're slightly more complex, though probably not much more complex of a swap. And I prefer the 5R over the 6R.
But by the time I'm actually able to start on the project, I might have to concede to do a 6.7. I don't know if they made non-PATS 6.7's though