The 38 two door sedans have great lines that make the hood look even longer.
These are great road cars too...
Add another $4-$6K and you will have a car worth much more...
The Buick 165 cu in engine has a threaded overflow on the left side of the oil pan.
Typically, there is a sight gauge (shown below) to show the oil level, but you really only need to fill it to that level.
Sealing reciprocating shafts is much more difficult than rotating shafts. These seals are usually directional to the high pressure side with V shaped sealing members that self actuate with higher pressure inside the V. In vacuum applications, the high pressure side is just the atmosphere. I believe you may need a cup seal:
https://www.mcmaster.com/piston-cup-seals
https://www.mcmaster.com/v-packing
Terry,
Just connect a good spark plug that is grounded to the negative side of a 6V battery. Connect the negative to the negative side of the coil and touch the positive side with the positive lead for just an instant to see if you get a spark from the spark plug.
We enjoyed touring with you and your dad on the Columbia Gorge Prewar Div. After Tour. I am sure he was at peace knowing that you will carry on with that beautiful Buick.