The Stovebolt Site Forums The Shop Area Engine Shop Degrees from top dead center

You mean piston movement down from TDC in inches?
It's really small for the first few degrees (like any other engine), and also corrupted by the piston pin offset.

Nominally, 1° is .0004" (not even 1 thousandth)
5° .010"
10° .038"
15° .086"
20° .152"
25° .235"
30° .335"

You'd be amazed at the number of times I've seen this: "The piston’s position relative to the top of the cylinder is the stroke length ÷ 180, times the number of degrees".