I haven't heard air out of the oil filler.
However....
I just re-torqued the head to 55 ft-lbs. Carefully followed the specified order. Most nuts were anywhere from 1/2 to about a turn too loose. Started engine and warmed it up thoroughly. Reran the compression test with these results:
Cyls 1,3,4 - Now at 57-60 psi, 5-8 psi better per cylinder.
Cyl 2 - Now at 37 psi, about 20 psi better.
As I think back over the events since I installed the head last fall, I KNOW of at least two times that it was re-torqued before today. Yet it still was off spec today.
Also, I inspected the old head gasket. The area between #2 and #3 shows a noticeable stain about 2" long and 1/2" wide, dark green to black in color. The stain starts on the #2 side and extends part way to #3. I'll try to take a picture to see if that sheds any light on this quest.
Now I'm headed out for a test drive as it's 59* and sunny. Too nice a day for a Model A to sit in the shop.
Back from test drive. Did about 20 miles. Engine ran well, and my co-pilot agrees that it has more pep. Now, here are pictures of both surfacea of the old head gasket. A question - is there a 'down' side and an 'up' side to the gasket? The first three pictures are of the side that lays against the head and the last 2 pix are on the block side. Is the large oval hole between #2 and #3 part of the cooling envelope?
All of this is bringing me to think that my leak down test was not done properly, leading to bogus results, and that the issue is/was head gasket. Any thoughts? Thanks for any help!