You will have to either buy/make the correct pins ,bosses , and other press parts to get them off . Or take them to a machine shop with the correct tools to press the pins out .
Piston Pins As stated by Lightning, they must be pressed off using a very high pressure press and a tool that will fit in the bore of the pin and also be a bit smaller than the outside diameter of the pin itself. There are special tools and piston supports for doing this but can be made if you have the material. When you get a rod on the press and apply 5 to 10 tons of pressure on the pusher pin, it will give you quite a scare when it initially breaks loose, something like a small bomb going off. Needless to say there is also a risk of breaking the piston and this is bad if you plan on using them over. Probably better off to let a shop do it for you to be safe. Have you tried to talk to the local high school or tech schools that have automotive classes to see if they won't do some of that kind of work for you? Usually free or at a small charge so the students have some learning experience. Just a thought on it.
are you putting new pistons on or reworking the rods. if not don,t remove them. if you have to most machine shops will remove and replace them for you for a price of course. if your not boring the block to a larger size and reusing the same pistons just clean them up.
