I've found that both my original 62 235 and current 58 261 both come alive at around 2400 rpm and will start to fade around 3000 rpm.
Recently I replaced the 235 Carb I had on my 261 with a 261 Carb and it will climb past 3000 a bit easier in the lower gears.
A few years back I drove a 660 mile trip in 12 hours at 3000 rpm at 60 mph and got better gas mileage than usual with complaints from the motor.
John
