Air dam / Air foil on cab roof or camper cab over?

Couple useless trivialities... I don’t list everything in my sig line because there’s no room and most here drive stock trucks and wouldn’t know or care... but my old Dodge makes a whole lot more than 375.
Also, 15 years ago, 500HP wasn’t uncommon in big-trucks.
The one I haul horses with is a 2000 379, one of those “aerodynamic disaster” but ultra-cool long hood Peterbilts. It’s got a 550HP Caterpillar C15.
It will indeed go over 93. But not with a few million $$ of horses in it!!