That cover is over the end of the camshaft on the timing cover. Just the way that particular cover was made. On the cackle car we used that spot to run the fuel pump. Which on a Chrysler Donovan timing cover, it uses a pretty big candlestick. The drive is a 3/8' hexagonal rod. You can see the set up right under the blower idler pully.
Gizmo is a cam position sensor (CMP.) The one I was building on top of the timing cover is crank position sensor (CKP.)
