TH350 stll useable?

I wonder if I should still try using this TH350. It has been sitting for a loooooong time and had a little water in the pan. no rust at all inside. It is still together. I can turn the output shaft easy and the inner input shaft also. The outer input shaft will not move. What does this mean? Can I test it somehow short of installing it in a car. I have had no experience on the inards. Not sure how they work.
Any ideas greatly appreciated.:HMMM:

That's the stator shaft, it doesn't turn. It holds the stator inside the converter.

I just took a 350 out of a street rod installed 700 it had a shift kit good trans $100 if you want it I'm in Middleton ma.