If you are using ACF 5 Pro you can export the field groups as JSON and import them into the new site and then you can export the posts using the WP exporter and import them to the other site. I can’t say if this will work 100%, but it should get most of the data across. However, anything that depends on ID values like image, relationship, post object, taxonomy fields and some others, will not transfer correctly and this data will need to be re-entered.
