Well, I like to use the Pete 386 (forgot the name in the game) and I'm with the Detroit Diesel 475 engine (Double Diesel in the game) and I can go pretty fast with it.
Bellow there's a picture of me hauling some good to Oxnard and I was in a slightly steeped hill and I hit 100 mph there, but I can go around 85 mph in a plain lane.
I wonder when I put the Cummins 565 when I manage to find it and if it is possible.