The exhaust manifolds were an issue for rams chevs and fords. The manifolds themselves are thin and shitty and warp as the bolts rot,maybe a common supplier?. Rams with mds had a lot of electrical gremlins too. The tritons had the spark plug issue and some would blow out and strip as the aluminum cycled and tensioners were plastic with a very long chains. Ford still hasn't bothered fixing the rust issue,new ones on the lot are rusting underneath( there is a lot of bare metal for such an expensive purchase) before they're sold. I have an 06 ram 4x4 with 550k on it ,not rebuilt and an 07 b4000 4x4 ,2nd motor, and the mazda is almost as hard on fuel but the handling is nice and the offroad is great as it's nimble and more fun. IMO the hemi is the best of the bunch due to its "simplicity" and the bottom end is strong but the cam and lifters are a weak spot and needs regular oil changes,i once tried to quiet it by using 5-30 and an alarm came up on the scanner telling me wrong oil but at least it still isn't rusty.. If i buy another truck,which is unlikely,it'll be a Tundra but they are quite pricey.