All for .370 lift and under ........

Dale.
Post #108.
I have a lot of cam catalogs from the 70s to 90s. The only cams in them that have longer int duration are cams for turbo engines, none that I could find for NA use. I do not see anything 'special' about mileage cams, other than their parameters are chosen for optimum low speed efficiency.
Some cam companies preferred single pattern cams, some used dual pattern, some used both. This was reflected in their mileage cams which simply had less duration & very often wider LSA.

Post #107.
Agree 10000% with your DV comments & tight LSA. But you omitted an important part of DVs cam comments: if you do not want a rough idle, you reduce duration. You do not widen LSA.