Any Pontiac guys on here? Need insight.

That disc acts as a flow restrictor... Oil can get around it... Top end doesn't need to be flooded with oil, it needs to be lubricated...
I do understand the purpose of the disk is to meter the amount of oil getting to the top end but, with it assembled there is no oil getting out of it which makes me think it should have hole/holes in it to meter the amount of oil allowed out of the inner chamber of the lifter as seen in the picture below. This disk has 4 small holes in it.

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