How Much Engine Oil?

Can you experts please help me with the correct amount of oil I should get out of this Chryslers crank case pan? The Correct Craft is a 1965 Barracuda and the engine was an entire swap out in the early 90’s. Below is everything else I know.

•     Very low hour, perfectly running 1990, maybe 80’s L 318 Mopar
•     On trailer, 3rd wheel full up, hull water flows very slightly toward bow.
•     Dip stick mounted port rear bottom of crank case reads right at Full line.
•     Cold, from inside oil tube sucked a hair more than 5 qts oil out, now dry.
•     Very Large PH8A (I know) held at least a ½ qt of oil.
•     Has no front or rear oil drain plug, only other is starboard rear bottom of pan.

Question is do I still have oil in the front dip of the pan and if so how can I get it out or do I have to add 5 fresh qts of oil to it.

Thanks…Scott