6.4 Hemi Ticking

I didn't know if this problem was related to specifically the MDS lifters or all as was said above. I will be tearing the engine down tomorrow and try to pinpoint the problem, starting with the lifters. And yes, somehow new cams are pretty cheap, surprisingly. And my father has an 03 hemi ram with over 270k on it and has had no engine repairs, no water pump, alternator, nothing, 90% gently driven highway miles though. Been running like a champ for nearly 15 years.