RPM on 3406 B cat

Hey I have a 3406b cat. And the motor seems to want to cruise at 1350-1500 rpm. Traditionally these motors are suppose to be wound up a little higher at least the others I have owned. I recently put a brand new (non reman) 13 speed trans. It is paired with 3.55 rears on high rubber. 1500 rpm puts me at 74 mph. 1350 puts me at 65mph and the motor and truck feel comfortable there. Good oil pressure and motor sounds smooth. Some have told me that rpm will wash out a bearing on these motors. I would agree if the motor wasn't running as smooth as it is. Will that rpm do damage or am I ok at these numbers?

My last 3406 b liked to run at 1625. This one doesn't feel the same that high up. It's runs more like my other truck c-15 cat.
Any input will help.

 

I set the truck up to run lower rpm at highway speed. My pyro is good. And yes my speeds are calculated correctly I specifically set the truck up to run 80-85 mph at 1700 rpm. At at 65-70 mph at 1350-1450 rpm is my optimal fuel mpg. 6.5. Which is good for a 1985 pete with a manual motor. And I seem to get that loaded or empty.
Thanks for everyones input seems like I'm good to go.

 

Which is my other point my boost is fine at 1350-1500 and my torque curve is on the middle to lower half. Which pulls fine from 1300. I really don't think I need to run it higher. I just wanted to see what you guys thought. This 3406 b. Just runs a lil different from my others.