 So I ordered a cover and marked the location of the crank pulley against the edge of the oil pan, and here's where I went wrong. After taking off the pulley, I didn't mark the crank sprocket against the block. Once I had the cover, I went to put it all back together, and before putting the belt on, I checked the crank pulley against the new cover, and they didn't match. With the crank pulley lined up on the mark I had made, it was way off from the mark on the cover, almost certainly a full tooth.