well the lowest miles I seen a lifter go bad was 120,000 (typical between 150,000 and 200,000 and as high as 270,000 on original lifters), I figure if it lasts another 120,000 minimum then I done all right. The dodge dealer told me all the part numbers are the same now for 6.4 6.1 and 5.7 without any other way to know what is best that personal experience is all I got to go on.