Bill:
Welcome!
The book doesn't list a '600' - but if it has a four-hole faceplate, it was probably a fleet pump or an airport pump. With four holes for the gallons - you could conceivably pump 9,999 gallons! OUCH!
You will need to get a three-wheel Veeder Root computer for your pump to use the aftermarket replacement face plates. The VR units are at all the gas bashes and on e-bay quite often.
Good luck with your restoration,
Later . . .
Jim
[This message has been edited by T-way (edited 01-19-2007).]