Many of the common Speed Graphic lens shutters are synced for flash. Unless it's a very modern lens it won't have a PC terminal though. Usually it's a bi-post. Others only sync via the solenoid which is actuated from the flash. The focal plane shutter, at least on the ones I'm familiar with, have a bi-post terminal as well, though the focal plane shutter needs a long duration flash bulb.
Some lenses may have an x-sync setting which could be used with electronic flash.

For focusing, are you using a dark-cloth? The focus hood on Graphics works, but a dark-cloth will help. Also you could try a loupe with less magnification.