"leaf" well enough alone - flash w/ leaf shutter lens

I have:
a 67II with the wood handgrip/hotshoe,
a AF500FTZ flash, and,
a 165mm/f4 lens. It's the one with the leaf shutter (LS).
Until now, I have been doing flash work the usual way, with the focal plane shutter at 1/30 sec or 1/15 sec.
What is required to allow the flash to sync with the leaf shutter? (what kind of cord?)
There is a short 5-pin cord connecting the hotshoe on the wood grip to the camera body. Can this be left in place when synching to the LS?
JH