Yes its possible, but in all honesty pulling the engine is a piece of cake. THe tricky part of doing it in the truck is trying to get to the rear bolts. Make sure that the shop does not re-use the old the head bolts as they are single use only!
Think I am just going to tackle this myself. Shop quoted me +1800. Oreilly sells gasket set and new head bolts for under 200. Don't have a cherry picker so I will be pulling the heads with the motor in the truck.
The heads are fairly easy to pull on the 5.7 hemi without removing motor. Manual says in order to remove heads that motor has to be raised in order to remove exhaust manifolds but the heads can be pulled with exhaust manifolds attached as long as manifold to exhaust pipe bolts, 2 per side, have been removed. Easiest way to obtain access to these bolts is by removing the front wheels and removing the plastic wheel well that is just held in by plastic fasteners. Removal took me about 6 hours total with hand tools and no air tools. Heads are at machine shop getting cleaned and tested with the valve seats being replaced and checking for possible curling on the intake valves.
You may want to strongly consider having new valve springs installed as the early 2004 5.7 engines had a number of instances where the engine was destroyed due to a collapsed valve spring dropping a valve into the engine.
If you have any damaged valves, I think I would replace all of them as well since you are in that far.
What is the build date of your D? Mine was 01/04 and the original Hemi died at 39K from a dropped valve.
2004 Durango SLT AWD 5.7 Hemi Flame Red with 3.55's
2004 Ford Crown Victoria Sport 4.6L Midnite Gray with 3L27's
2011 Hyundai Santa Fe GLS AWD V6 Mineral Gray (Hers)
The valves are in good shape, luckily the overheating did not affect them. I am not sure of the build date, I will have to double check. I do know this is our second motor in the Durango. We replaced the motor around 220K miles with a used motor with about 56K miles on it. This was the first issue we had with this motor after adding another 140k miles to it for a total of about 360K miles on the Durango total. This was not motor failure but unfortunately driver error. I replaced a leaking water pump and had someone attempt to top off radiator with coolant and did not secure the radiator cap completely and blew the motor after overheating. Yikes.
Machine shop got back to me and stated we have about 0.013" warpage on one head and 0.016" on the other. I have a replacement head gasket set and meet the stock requirements of 0.0028 compressed thickness. I am thinking about ordering some Cometic gaskets that can be purchased in different thicknesses to make up for the milling.
I am getting ready to do the same thing to our Jounery with a 3.5 V6, can the cam be removed with out pulling the engine. I need to change the cats also so I'm hoping it can be done with out pulling it.