need to look at the inside of the cam cover. the factory sealant
cracks thus allowing blowby to go straight into the air filter.
check it out and reseal the baffle inside the cam cover.
as to lifter noise i would switch to mobil 1 15/50. might take a couple
of changes. if it still is noisy then you got a bad lifter or a bad
rocker arm/camshaft lobe. on all early v8's the cam oiler tube
holders like to come loose with age and don't allow full oil flow
to the cam lobes.

george