416 low oil pressure at idle

Before you start blaming it on parts, look at your oil.

You are running 20w/50 VRI.

Look at the viscosity index of that oil.

At 212 degrees F/ 100C it's at 20.5
At 104 defrees F/ 40C it's at 181.8

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1496497

20w/50 is going to act like that. It's going to jump up in thickness/viscosity at low temp/ cold start and go down to around 10psi per 1000rpm at running temp, because it's engineered to protect parts under heavy use and this is consequential.



Listen to your engine builder. Every engine is different. If you were running 10w/30 or something lighter, you may have some concern on good seal on moving parts with tolerances, but the numbers you are seeing in oil pressure drop are normal for an eccentric viscosity index oil like that.
ne
when I talked to him today, he said to change to straight 30, I was running the Valv (not street legal) 20/50, he also mentioned that since we almost overheated last week, (temp got to 220+) we may have broken down the oil ??? said to dump it and go straight 30 ???