They have a timing chain and are a pushrod engine. Good,powerful engines but in the Durango of the era they had cowl panel that would let water drain on top of the engine.(There is an updated cowl panel to fix this from a later model) When the engine has some miles on it,the water can be sucked into a cylinder being it through the intake seals or the relaxed MLS cylinder head gaskets.Hydrolck and a broken or bent connecting rod is the result.Usually with block damage.If you get a good runner,update the cowl panel before the carnage! Jeep Grand Cherokee's and the Commander's could be had with the Hemi but no cowl issues on them I know of.
RT