An implantable electrical medical device system includes a device body portion having a plurality of contacts operably coupled to discrete channels of electronics. One or more swappable headers may be attached to the device body portion by an end user, such as an implanting physician, to operably couple internal lead receptacle contacts in the header to the contacts of the device body portion. The swappable headers may have lead receptacles configured to receive differing types or combinations of leads, allowing an end user to select one or more appropriate headers as desired.