Ok since we are on the subject of the extra length of the cam shaft.....
it is for reverse on the tillers. Which in my opinion are dangerous. Just inmagine if you will..........tilling away at the garden wether it be a flower garden or a vegitable garden. Most folks around here put up little fences to keep varmits out, which dont help much, and you decide to use reverse.... You are tilling back wards at full speed and the engagement lever gets stuck, you trip over the little fence and the tiller runs you over..............Then you look like me with no legs................that is why I wont hook reverse up on a tiller.
Now back to your story.....
Just cut off the end, flush with the sump cover. it dont need a special plug or any thing and dont go tearing it apart to change the cam. Cause then you will need a pan gasket because if it hasnt been changed in for ever.... it will break on you. But it is your stuff do what you will. Just my 2 cents.