Boost pressure

[Blueovalnut]

Hello to all, I recently bought a used diesel pusher Motorhome that has been de-mandated. It runs good, but the boost pressure is 34-36psi while driving on flat highway at 65mph without towing anything. The highest boost pressure I’ve seen is 39psi during heavy accelerating. The 34-36psi on flat highway driving seems high to me. What do you guys think? Also at idle it has 2-3psi and sounds like a jet engine getting ready for takeoff. 2007 Cummins ISL 425hp in 42’ Motorhome. Thanks in advance for your replies and for letting me join the forum.