The old N's used thin wall sleeves and they are easy to peal out with an old screwdriver, no need for a special tool. To install new ones the easy way is to freeze them and keep them frozen until you are ready to install, I keep them in a cooler with dry ice on installation day. Be sure to clean the block to remove ALL rust and debris. When you go to put them in do it FAST and push it home immediately so it will all the way down cause it is a $*%& if they don't go all the way down.