Synthetic Oil Improvement in /6

15W-40 Rotella T with Triple Protection oil has approximately 1200 ppm of zinc...
Thats pretty good for a Walmart oil when it comes to solid lifter cam motors..

Hey, thats odd. I got a sale add today from Advance, with Rotella on sale.
Isn't that diesel oil, or am I being stupid?
Is that okay to run that weight in my slant 6 until I toss my V8 in it next summer?