FSU and Clemson go to the SEC and WVU also goes to the SEC. That will leave the ACC with 12 teams. The ACC then adds UConn, Rutgers, Louisville, and South Florida to get to 16. If Clemson and FSU don't go to the SEC, then Louisville and South Florida are left out of the ACC.
ACC North
Syracuse
Pitt
UConn
Rutgers
BC
Maryland
Virginia
Virginia Tech
ACC South
Miami
South Florida
Louisville
Duke
NC State
UNC
Wake Forest
Georgia Tech
The ACC North will look a lot like the Old Big East, just trade Maryland and Virginia for Miami and West Virginia.