I'm running the 15/40 Rotella now myself. Formerly, Castrol GTX 20/50. I've always stayed away from
synthetic in my FE for the same reasons some old timers stay away from it in Harleys; slippery, no stick, no climbing.
Man that Rotella sure smells. You know as soon as you put it in there. The first time a ran it with Rotella, I could actually hear a slight difference in how my valvetrain sounds. Being so in tune with my solid lifter valves/sounds, with this new
oil, it actually sounds a tad smoother for whatever reason.
If anyone has more current updates from cam companies or engine builders on additional findings regarding long-term use of Rotella would be appreciated. Thanks,