Wiped cam/lifter?
Reading your post gave me chills down my spine... I experienced the SAME THING....only after 20 miles on a freshly built engine! If you pull the valve cover you *should* be able to see inside through the pushrod openings with a STRONG LED-style flashlight. Look at the lifter/cam lobe area.
If you see carnage, get ready to yank the engine. Why? Because all the metal that's missing from your cam & lifters is IN your engine. Circulating through your oil passages...bearing surfaces...oil pump drive...
Sorry for the bad news. But like the saying goes: been there-done that. :angry7: