Greg,
Your right about the flywheel rotation. If one were to rotate the flywheel so the BB and little pointer lined up perfectly, this would be TDC...where #1 plug fires.
Any flash of the timing light BEFORE this point would be ADVANCE. Any flash AFTER that point would be RETARDED.
All engines run with some amount of advance. What I have never know is if the Chevrolet engineers built some advance into the pointer/BB relationship...maybe someone knows.
The pointer/BB alignment happens twice during the two rotations of the crank. One alignment is correct, and one isn't!
Stuart
