Hi, i am looking at a M-20 trans for my 64 malibu. It came out of a 71 or so i am told. It shifts through the gears very well and doesnt have any cracks or any kind of problems and it will not need a rebuild. The guy gave me some numbers and i was wondering if anyone can tell me anything about this trans? Like what i should offer the guy for it. It is going to be put behind a 325hp 327. Will this is a good trans for the job? I only have a saginaw 3 speed on the tree and would like to switch when i put in my new engine.
Here are the numbers he gave me.

They are 3925669,3851325,3885010. Not sure what they mean but thanks for any help.