I would imagine the monitor is a normal arcade monitor so your AVGA card shoud drive it properly, and since it is JAMMA wired, your JPAC should work nicely with it.
I know the guy and I may be going over there this Sunday to check out all his stuff.  
I have a PC and a JPAC that he gave me to configure for a MAME setup.  I will bring that stuff with me to see if it will run in his Candy Cabs.