Since this thread started as a timing question there is one neat thing I would like to share. I always recomend useing a degree whell and light to check timing, however on a flattie you really don't want to pull the head to find TDC. On some engines I worked on in the military they had two crankshafts, one on top and one on the bottom, the pistons upon reaching the end of their stroke formed a "head" (the bottom crank led by a couple of degrees). In order to check wear we would use soft lead with a wire melted into it, stick it through the injestor port and crank the engine over. We then miked the "crush" and knew from the last time how much wear in the bearings we had.
Point is: take a lead sinker, flatten it a little after you insert a wire through it and put it in the spark plug hole until it's above the piston, rotate the crank until the lead stops it, go backwards noting on the degree wheel, split the difference and you have TDC without removing the head.