When a converter is classified as say a 10" converter, is that the case size or the internals?

The first reason I ask is so I don't talk out of my a$$ when talking converters, the second is my converter in my blazer is smaller than any I've used before and I'd like to have an idea of what it is before I sink any money into it to have it rebuilt because it makes LOTS of noise.

http://i56.photobucket.com/albums/g163/slowride454/blazer%202007/DSCN0437.jpg
http://i56.photobucket.com/albums/g163/slowride454/blazer%202007/DSCN0438.jpg

the red one is a Hughes GM25 for reference and the small one is of unknown origin. Previous owner was told it is a Coan, but I don't know for sure. There are no marking on it at all.

Sorry for the dumb questions.

There are no "dumb" questions only questions that are not asked are dumb :)
With that being said, you may want to post this in the transmission section if you dont recieve many replys. There are a few experts that visit that column that should be able to help you. I think jakeshoe is one of them.

Bill

I posted this on alot of sites. No real answers. Some have said they've heard of putting 8" internals inside a 9" case for better heat disapation, but at a loss of efficiency. I'm probbaly going to get this converter cut apart to see what is wrong with it, but with it being of unknown origin, it might not be worth the $$$$.