Peel peaches. Cut 2 peaches into chunks and mix with 1/4 cup sugar. Puree the other peach and the lemon juice in a blender. Heat the evaporated milk and milk together. Stir eggs and remaining sugar together in the top of a double boiler. Slowly add hot milk mixture, whisking constantly. Add sweetened condensed milk and peach puree. Cook, whisking constantly, until mixture is thick and coats the back of a spoon. Remove from heat and cool. Stir in vanilla and peach chunks. Freeze in ice cream maker according to manufacturer's instructions.