Resuming at 300 for five, Himachal went on to score 554 in their first innings.
Starting at his overnight score of 111, Gangta went on to score 203 before being dismissed by Mohammed Mudhasir, facing 321 balls and hitting 27 boundaries, including seven sixes.
Bipul remained unbeaten on 117.
Later, Jammu and Kashmir were ended the day at 85 for one in their second innings with opener Shubham Khajuria (31) and Paras Sharma (14) at the crease.