Thought it was lifters or cam lobe. Rechecked lash, one was a hair tight, readjusted, but nothing loose so figured it must have been a lifter.
Restarted car, it was fine. Maybe just took a bit to get oil through the oil holes on the faces. Smeared a good bit of assembly lube on them and the cam.
Anyhow, restarted car, it’s fine now, let it run a good while, no issues at all. Topped offradiator, added water wetter, all good.! Lash perfect
Fixed valve cover leak, no leaks now, all dry underneath