New rider, 77 KZ400

I must say I am glad I found these forums, and I am sure I will find a great deal of information on here. I've learned a lot already, but have a few issues now that I'll get to later.

My KZ400 is my first motorcycle. I bought it on ebay last fall from a guy local to me (Buffalo, NY area). I had no chance to ride last fall, so it went into storage with nothing but a little stabilizer in the tank.

As you can guess, I had a hell of a time getting it running this spring, but after cleaning the carbs and replacing the spark plugs, I was able to get it running and idling fine. Then I decided to mess with success by getting some fancy chrome pod-style air filters, instead of the UNI pods that the PO had put on there (to go with the cafe racer look, apparently).

Now, it's been nothing but downhill for the last few days. I went from a running motrocycle to a pile of gas-soaked parts in less than three days.

Biggest current problem is the petcock -- unlike most 77's, it doesn't leak. Unfortunately, it doesn't allow gas through at all, so the bike won't run. Realizing that I needed to remove the petcock to fix this problem, I removed the tank and attempted to pour the gas out of the top. Apparently, this is a really stupid idea. I now need to repaint the tank, too.

Meanwhile, the headlight blew, and I discovered that the trim ring is rusted through on the bottom side.

So, I'm now looking at either replacing the petcock and repainting the tank, or just getting a whole new tank with petcock. Since I need to fix the headlight, I might as well upgrade to the h4-style, which would be all chrome, so no need to match the paint. Then I'd only need to paint the side covers to match the tank.

I'm curious as to what other Kawasaki tanks might fit? Am I stuck with 74-77 KZ400 tanks?

Thanks for all the excellent info here, and any advice you can give.