We use an old gear and shaft,place a used bushing upside down under the gear.Start the new bushing in the block bore.Using a drift pin slowly drive the shaft with the inverted old bushing driving the new bushing into the bore.Go slow and stop a few times and spin the old shaft in the new bushing to fit the bore,use a light oil on the shaft.When your done the shaft should rotate freely and the new bushing should be seated with no damage.We have a shaft with much of the gear machined off as to not interfer with the cam gear since we do this installation quite often and the bushing replacement alway goes well.For removal in a block we use a 1/4 inch socket extension with a small socket that fits the bore and contacts the bushing driving it out.