Well, I found out what it is. I had to cheat though. I admit it. I asked the only person that I thought would know and sure enough, he did. Immediately.
I've been trying to get him to join autopuzzles but so far he hasn't. If he did, I fear there wouldn't be much left unsolved. I'll keep working at him.
Anywho, it's a Unic U6 3-liter.
I've never heard of Unic, but it is a rather unfortunate name when spoken aloud. I don't think they'd sell very well in the US.