360 Magnum Cam bearings, what causes this?

Hi Guys,

Went to change camshaft today and found this, what causes this and can cam bearings be changed with crank and pistons in place?

twisting and dragging the cam while removing?

I've seen cam bearing flaking more than once. It isn't from oil starvation or dirty oil though. Most likely cause is so-so quality bearings and the wear layer starts to flake away. I haven't seen them cause any problems and are only found at tear down.

You can change cam bearing with the crank in place. You need a cam bearing installation tool kit to both remove and install them though.