Isx cm871 chirping at idle

[Skylgue]

Hi, we've got a 2009 kenworth t800 with an isx cm871. There's a loud chirping noise at idle coming from the driver's side of the engine. I've narrowed it down with a stethoscope to an area on the head next to where the jake harness goes in. We've just put 2 new cams and rockers since the old cams were very chewed up but that didn't fix the noise. Injector cam bearings looked alright and weren't changed. Ran it with the valve cover off and all the injector cam journals are getting plenty of oil (doesn't look like a spun cam bearing). When you rev it past 1200 rpm the noise fades away. This truck had no emissions when we bought it used. Any clue what it my be or what I should look for?