Cam Operating Range & Highway Driveability

I currently have 273 gears and the 42RH overdrive with a mild cam designed for 3,500-5,500.
Bonneville was back there a few off ramps.:D

I am finally about to start on my 8.25 locker with 355 gears though, which has always been the plan.
Whats that like in a 35 or 45 mph zone ? Even with OD off...