I know I recently pm'd someone that I had no interest in doing a 4.7 swap after they suggested it. That said...I'm considering it. After going through some considerable research, I've decided several things; 1. for similar years, both the 3.7 and the 4.7 have the same block casting to the farthest forward hole, tho the 4.7 obviously extens one more cylinder 2. The 4.7 is really only about 4 to 5" longer than the 3.7 3. The intake for the 4.7 would pretty much fall into the same location 4. If you use the 3.7 harmonic balancer, a/c pump, and alternator, which all bolt up, then you will be able to use the OEM serpentine to your vehicle, eliminating hassle when ordering parts 5. While the flange on the exhaust manifold may be different for the forward cats, it would not be hard to rectify that problem 6. Everyone is overthinking this swap. Here's the basic deal. A 4.7 will bolt up to the 45RFE trans that are in all of my 02 KJ's. Likewise, based off of my measurements, the 3.7 motor mounts will bolt directly to the 4.7 block. Assuming there are no real issues with the oil pan and clearance (which it is more likely that there will not be, as they were designed off the same piece), the motor should actually bolt right in. If you do not run a mechanical fan, there is actually enough clearance in the engine bay to put the non-mechanical fan shroud with e-fan in, and add a pusher fan from a CRD That said, the KJ's radiator might not be enough to cool the 4.7. I'm sure that there are several aftermarket full aluminum radiators available that could remedy that problem. The intake manifold places the throttle body in darn near the same location as the 3.7, if not exactly, if you are using similar year. Likewise with the fuel rail and where you hook it up. A longer hose might be necessary, but no big deal. As far as wiring and sensor issues etc... If the donor motor has the proper tone ring and cam ring (whatever you call it), with the matched similar year ECU, modifying the existing harness to be compatible with the v8 harness (or vice-versa) would be pretty darn simple. The only real problem that I see is whether the tachometer will read properly...which it should based off of the information I'm finding about tachometer signal. This whole deal is really pretty straight forward in my opinion. I guess the next thing I'm going to need is a 99-02 4.7 longblock, intake manifold, fuel rail, flex plate, and exhaust manifolds. I really don't even need a good motor, but I'd like to mock this up and put it in my liberty to show just how possible it actually is.