You still have too much air volume before it gets to the pump.. 2 -12 lines is a lot

Went out today. Started the car.
One day later and I have oil pressure immediately.

So why do I lose prime in 3 days?
Wouldnt the oil drain out the filter overnight?

Would a check valve at the lower -12an fitting on the pump prevent this from happening?

Do you want to risk the chance of it not opening on the start up... I dont know of anyone running one

That's why I would only use just 1 check valve, the top fitting would be used as a backup and be the primary suction line if the check valve failed.

Wait 3 or 4 days now and see what happens then

Why not take one of the pick up lines off.. keep the flattest line

After rerouting the oil lines, I thought the problem was fixed.
It isn't .
Much better oil pressure but still takes a good 15 to 20 seconds to prime.

Did you ever measure the clearance between the pump cover and the rotors ?

Back on 3/15/2020 you said this all started after installing a Moroso filter.

Did you go back to a filter that never gave you problems?

This problem Started after new Milodon oiling system and Moroso oil filter. Moroso was a breaking fine micron filter but changed it out to a regular Wix racing oil filter and pressure did go up to 82psi from 68psi cold..
Priming issue still the same enough. So it's not the oil filter.

A oil pump has very little draw until it gets oil in it to seal it up.. in your case you started with 2 lines and
at least one line went high.. oil or any liquid will always take the path of least resistance.. keep a
small trap point and dont make the pump work hard.. your pump may be screwed by now

I'm thinking that the oil filter is draining out over the 3 days.
A $40.00 check valve might be the answer.
Going to leave the top line without a check valve.
If this doesnt work, I ordered 2 -12an threaded caps and will try just 1 line to see if the problem goes away.

Most all oil filters have a anti drain back valve.. so does Wix

so my question is, if theres oil in the filter, why wont it prime? I guess the oil out of the pump must be draining back over time.

If you have a trap in the line close to the pump and the pump is in decent shape it will prime..
have the oil line low enough that it has oil in it.... take a pic of the oil line and post it

It's almost exactly like Prosports except my other line goes straight across to the front of the pump fitting.
Not sure why it loses prime in 3 days but not 2 or overnight.

If the gears have excessive clearance the oil pressure will take time. The pups don;t pull well, they push. Have you looked at them? Mine runs a single line, Indy cover, swinging pick up, Wix filter. Never an issue. On my previous car; dual line Milodon with worn pump gears was very slow to build pressure. Either way an accumulator will solve it.
Doug

I just received the -12an check valve and I blow in the end that is suppose to close and seal but it leaks air!
Shouldnt it be sealed tight with no air escaping?

Now I ran water through it and it doesnt hold, all water escapes through it.

Boy does Murphy love messing with you