I had quite a time trying to get my side ones out. All I was doing was creating more holes. Then my machinist told me to take about a 1/2" dull chisel, and hit it on the side to tip it in so that the other side tips outwards. The next step is to grab it and yank it out. Those ones on the side of the block can easily be knocked right inside the water jacket, and then the fun begins!
