Mostly Rotella 15w-40. I've also run Delo, Valvoline and Delvac, doing oil analysis with each to see if any one seemed significantly better than the others. As for the filter, it's been the Motorcraft FL-1995 that you can buy at wally world or most parts stores for $10.

Oil change interval has been 5,000 miles for me.

 

Thanks for the feedback. I am with the same plan as you, ( I've used Rotella, Delo and MC oil and always the MC #1995 with 5000 OCI). I am now sticking with the MC oil because it is good oil and at a decent price at WW in the 5 qt jugs.