440 initial timing mystery

My guess is doing an excellent job with a camera, at best you might get to 8 degrees of actual timing. You will get a better number using a dial indicator on each side of TDC, to get the same reading at least 20 degrees apart. The travel is flat near top, that is why best to use sides and split.
Here is a good article on piston travel. Piston Motion: The Obvious and not-so-Obvious, by EPI, Inc.