Help! It won't move!!

You didn't state what year the trans is???? If it is an early 64-65 trans the output/pump shaft is different than the later trans'. If I'm not mistaken the converter you installed if for later 904's. I know a few people who ran into this, it feels like it seats then nothing when you put it in gear. When I had my 64 p/button trans redone I had a later front pump assembly installed...

Bob