highway cruising with 4.10 gears
A lotta boats with all kinda engines cruise over 3k for hrs, under heavy load, and 4k is not unheard of,, ask me how I know..
I used to drive 30 mi on hiway to our strip ,, all summer long,, 5:12's 3500 rpm..
Tailpipes out to the back reduces the drone,, as do the mopar resonators..