How to verify crankcase oil level on a /6? Options

[tornik550]

I also posted this on pp however I usually get better responses here.

I recently rebuilt my 2.7l. I have the engine on a test stand. The oil tank is mounted at approximately the same level as it would be in the car. I am questioning the actual oil level in my crankcase.

I put 12qts in the tank. I cranked the engine without ignition to get the oil pressure up. The dipstick doesn't show any oil so I put a couple more quarts in and it still doesn't show on the dipstick. I suspect there is actually too much oil because I can see a little bit of standing oil in the cylinders with a scope. It is not oil from assembly cause it was a different color.

I am using a used 911 oil tank from an unknown engine.

Normally I would just wonder if my dipstick was just not correct however since the setup is on a test stand, I wonder if something else is going on and I would like to verify the oil level in the case before starting the engine. How can I do that?