Stupid and heavily debated question..

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   I’m just skimming the last couple posts here. My .01$. The mention of diesel spec is true. Changed. There was/is some backwards compatibility but bear this in mind. Diesel oil’s job is very different. Many diesels are running roller cam gear. And all have to have high detergent. That can but not always interferes with the EP or ZZDP. Some diesel oils have reduced and reformulated the Antiwear package. Some are better now than ever, but do the research. HD oils have been a reasonable way to go, but double check. 
For reference, an oil like Swepco 306 still has a solid combo for our valvetrain. They sell a booster for that additive package as well. It’s a good bet, if a little hard to find, and a touch spendy.

In oil tribology, additives work as a package. That is important to accept. 

I like the Valvoline VR1 conventional. I run it in a late 4.0 baby Jeep. It’s not well spec’d for long drain intervals. But it has solid antiwear and base stock. That said, I feel it runs light. I haven’t looked up it’s spec. I have run the straight 30 and like it better when it’s cool out. It flows good cold, as does the 10/30, but those late model pistons don’t sound good with multi grade when it’s cool out. (Western Wa) VR1 is reasonable in cost ~ 6.5$/qt
Even with an injected 4.0, I don’t go long intervals with it. 

Our old AMCs (some) have the exhaust crossover and EGR. That, I have found is really hard on oil contamination, and cooks the already old valve seals, which of course make things worse. Those things dramatically effect mixture and carboning, even with EFI added. HD diesel oils do well with acid control, sludge control, detergents and dispersants. 

Blah blah. Hope this is helpful 