They surpassed the previous record of 263-5, set by Royal Challengers Bangalore in 2013
The 31-year-old Sohail suffered back spasms and missed the three-match one-day international series, which Pakistan lost having gone down in the first two matches.
Imran, 27, has played three Tests for Pakistan, who have also lost batsman Sohaib Maqsood, paceman Yasir Shah and leg-spinner Yasir Shah for the Bangladesh tour through injuries.
The first of the two Tests start in Khulna on April 28 with the second match in Dhaka from May 6.