The 388 does have sync capability though. You would have 14 tracks for audio though as each machine would have 1 track used up for the SMPTE code.
So there's the two decks and then a synchronizer would interface between them like an MTS-1000, ATS-500, ES-50 from Tascam, Timeline makes units as well...the synchronizer "listens" to the timecode from the master machine, and "listens to the timecode from the slave machine, and then controls the capstan motor on the slave decks to modulate the speed of the slave machine so that the timecode lines up between the two.
Beware that if you do not have the cables that go in between the decks and the synchronizer it can be a real fun challenge to build that cable. The 388 uses the same cable that is used for the 48, 58, ATR60-series, MS-16...ELCO on one end and then the other end depends on the synchronizer, and its not just a simple cable. There are components in it (diodes, resistors, etc.) You need the cable schematic from Tascam (or I put it up here somewhere...I have it) as well as pinouts for the synchronizer.
I built a cable to interface my 58-OB with my ES-50 synchronizer. It was a fun but intensive project, and I required lots of assistance from anumber of users as well as from Tascam.
Not trying to scare you off of it, okay? Just sharing my experience...Pianodano said to me over at the Tascam Analog Forum when I started getting into this "You in deep now..." He was right.