Best Commercial Engine Oil ???

That's a boat load of information

 

I like VALVOLINE blue, get good lab results from a DD15 and 40k oil changes
Less than 5% idle time.
2nd choice Delvac

 

My 3406B hated Delovac and loved Rotella (Delovac burned 1 gallon in 10k Rotella burned 1/2 gallon in 15k)
My 12.7 Detroit was the exact opposite.
The company Volvo with a ISX 15L loved Rotella
The company Volvo with the D13 loved Delo
It can only be determined by you in your own engine as each is different with tolerances varying on each build.

 

I had a recent experience with same oil brand but different formula.
I have a 3.9 powered impala with 80k on it ...been on mobil 1 5w30 for the last 50k .
6 months ago it abruptly started using about a qaurt every 1000 miles.
Checked out Bob the oil guy site and switched it to mobil 1 10w30 high mileage formula and it completely quit using oil within 2 oil changes.

 

I ran Premium Blue Xtreme in my 12 valve the whole time I owned it. I like that oil too.

 

One thing I learned. My 5.0 Ford HATES Lucas. Thing made all kinds of knocking noises. Wasted $80 worth of good oil by contaminating it with that stuff. Dumped in straight 5W-20 and never had an issue again.

 

I use Schaefer’s 15-40 7000 Semi Synthetic in my 12.7.