How should I start no oil to rockers

Many Many thanks to the member that suggested to remove the oil pump relief valve!
I.is best to start at the source.
What a surprise!
There is no spring and no plunger!
It would seem that decades of prior repair work has taken its toll. I just got the Valiant and I am nursing it back to normal. It must have had a low oil pressure problem I would guess, and someone did a bandage to fix it. The oil pressure light worked and only showed normal flickering at idle when I got it.
I will get a new oil pump and try to replace it per factory service manual.
Thank you all for your help.