Engine hours vs. Miles

[tree98]

I have a 2007 kenworth with a cm870. It's a log truck with a hydraulic log loader mounted to it. The hour meter keeps ticking while the operator is loading or unloading so the motor has 20,000 hour's and the truck gas 370,000 Miles.For maintenance reasons I'm trying to figure out how many miles would equal 20,000 hour's? Anybody else have this many hours on an over the road truck? If so how many miles does it have?