Just picked up a 14 Jeep SRT with 23K on it. I know it needs 0W-40 so the MDS works correctly. I was thinking about running amsoil signature series 0W-40 and was wondering if anybody had any real world results with the amsoil in the big 6.4 Hemi?
Please note that MDS has been proven to work well with almost any weight of oil. The same valve gear is spec'd for everything from 20W to 40W.
Amsoil is excellent oil but modern synthetics are all probably better than needed, especially for street use only. My 6.1 carries a TSB for 50W if desired when oil temps get hot and the piston squirters whine/warble.
I must reluctantly recommend the OW-40 Pennzoil oil as well as it is the only oil currently certified for your engine. Mobil 1 0W-40 is right on my oil cap and would serve you well, too. But who wants to give them an out...