Oh, to knock them out I use a socket and hammer. Put the socket to one side of the plug and slowly tap till the side your hitting starts to go inside the block. This will pivot the other side and grab it with plyers or vicegrips and yank er out. Just don't knock it inside the block!!....been there, done that. Cover the inside of the new plug and lip with a good sealer and re-install new plugs using a socket close to the size of the plug (big!) tapping in slowly and evenly. I'll get that number.....G.