Gas tank question

Anybody happen to know what size the petcock nipple is on a KZ1000 tank?
What it is is, I bought a cheapo barn find 1971 H**** CB350, to teach my wife how to ride.
It has everything but the gas petcock, so I really don't even know if the thing runs yet, but the motor isn't locked, the odo says it only has 3K miles, the chain appears to be un stretched, and the paint ain't too bad.

The nipple on the CB350's tank measures .621" (or 15.77mm) across the threads.
Anybody know what else might fit without me having to weld an adapter onto it? Them CB350 guys are sure proud of their petcocks.

the bung on the early kawi's is 22mm that honda may be a keeper some of the real honda guys would just about kill for that bike check out what they are going for on e-bay. you might be able to make some quick cash if it's in decent shape.

Thanks timebomb.
Yeah, I was thinking if this thing turns out to run good and not burn a bunch of oil, I might clean her up, polish the aluminum, replace a few rusty things and see if I can turn a buck on it.
Unless of course, my wife gets attached to it.:laugh:
I'll post a couple pics one of these days.