Thanks Bob in Ct. Like everything else around here, once you cut through the advertizing hype, you find out what works, and what doesn't. And whose product is more high tech than their advertizing. And again, it's the guys with the dirty hands (and grease on their keyboards)who know. Specifically which Mobil1
oil filter are you using? Can your 351W in a SPF use a full length Ford filter? In a CR, it's too long, and the other options I found are shorter ones that Ford uses in some vans #43, and the 302 Mustang II #16. I seem to recall the #43 cross references to SB Mopars as well.
Like many of you, before synthetics, I used Quaker State, Valvoline, or Castrol; changed
oil and filter every 3 - 5K miles, and could eat off the inside of the rocker covers after 100k miles.