From time to time I get delusions of grandeur and think that maybe, just maybe, one of the new higher ups at the newly reformed Chrysler/Cerebrus will listen to gripes about the motor in the Jeep Wrangler JK. I am sorry, but the 3.8 liter motor from the CARAVAN that is in there now just breaks my heart. I would love to buy one, when and if they put in a decent motor. So what kind of motor would you put in to the JK if you could have your druthers? Let's just go for full dreaming (no worries about if it will fit, that is for the engineers...) I am going to have one gas and one diesel motor as I think the platform deserves the option....so here goes. Let me know your dream motors! Who knows, someone might read this!
DIESEL- VW 6.0 V10 Turbodiesel.
GASOLINE-6.1 liter Hemi from the SRT Chryslers
As I said, let the engineers worry about them fitting.  

The V-10 turbodiesel is a dream, bro. Don't hold your breath. However, I think the 3.0 Mercedes turbodiesel from the Grand is a possibility, and after going for a ride in it the other day, I think that would make a dandy engine.

I do think a gas V-8 option would be appropriate, too. At the very least the 4.7, but the Hemi would be even better.

But for sure the 3.8 minivan engine is pretty weak-sauce. It's got to go.  

My top choices?

4.7L Hi-Po
2.8L TDI from Liberty (that's what is in jeeps outside the US anyway)
3.0 Mercedes Engine from the Grand
5.7 Hemi

I personally like my Jeep light, nimble, and stable, so the heavier engines wouldn't be my choice for power.  I don't know how heavy the 2.8 or 3.0 are, but diesels are heavy.  The driveability and fuel economy would rock the house though.  I am considering a 4.7L swap right now into my '06, just because I haven't seen one yet and I think it would be about right.  To be honest, I don't get too wild off road compared to some of my friends.  I like the 2.4L in my '06, now that I have a Jet chip, intake, yada yada.  If I don't swap in the 4.7, then I will probably put a supercharger on the 2.4 and run it like that.  I like that little mitsubishi motor.  I've been hard on it with no problems yet. It goes right on down the road and is so light in the front compared to my '89 4.2L Wrangler.

I hear that next year Dodge is putting the 4.0L Dodge Nitro engine in there.  That could be cool.  A diesel would be neat, maybe like a little 4 banger Cummins or something.  

The Nitro 4.0 would be a nice upgrade. Somebody told me because of crash standards, a V-8 won't fit up there. I find that kind of hard to believe. V-8s are typically only about 4-5 inches longer than an equivalent V-6. You wouldn't think it would make that much of a difference, but maybe it does.  

My in-laws are big fans of the Cummins turbo diesel. After driving the brother-in law's truck to work one day, I was a changed man. I think an updated 4 cylinder cummins would be a perfect for any Jeep. I also would like to see the 2.8 or 3.0 CRD's that have been all the buzz. The 3.0L CRD just seems like a good choice as well since it is already offered overseas in many of our favorite vehicles.