Master cylinder help

I took the master cylinder off my car today, and I'm trying to figure out what kind it is.

It has this stamped on the bottom-- USA 29966-C. It's 7 3/4 inches long from end to end.

Any ideas? I need to buy a rebuild kit if I can find one.

Thanks..........

 

Nobody else has taken a guess so I will. It looks a bit like the one from a Volkswagen bug, but it's been a few years since I saw one. It must have a remote resevoir, correct? What are the threads on the brake line fittings, are they metric? What did it come out of? Do you see any other markings on it, or the resevoir?
Red

 

Back from the dead, I know.

I was just directed to this page...had a phone call from a customer looking for this particular master cylinder....I know what it is, so It might help someone....someday.

Its off of a 1981 Buick Century (among others). The OE part has a plastic reservior on it. Whoever did this has obviously gotten rid of the reservior and machined their own remote reservoir fittings.