I have a 97 F-250 hd 7.3l powerstroke 4oed with 3.55 screws with 230,000. i always use motorcraft filters so i am looking for a good oil and since it is summer i was thinkin a 30 wt flavor. i was wonderin which 30 would be the best? i was thinkin 250 hours, 6,000 miles on dino, 350 hours 10,000 miles on syn. that seem tolorable, i am running 85+% highway? does amsoil still have there hdd 30wt?
ken