You don't know what you are writing about, that much is clear. Chevy/GM people did this all the time to get rid of the failure prone m21-22 boxes. Hacksaw away!
It has a vin stamped in it, that should be your first HUGE hint, but you choose to remain on this hunt to prove yourself correct. Which cars from that plant would have come with an 18 spline box?
That trans DID NOT leave the factory in its' current configuration. Now you are just trolling hoping you found a Willy Wonka Golden Ticket only to find out it's not what you were hoping it to be.
Is it a nice 18 spline trans that will go in an A body, yep... congrats on that. If you paid strong money for it because someone sold it as a SS trans... you're now getting an education in 18 spline transmissions. Caveat Emptor. Beyond that, it's nothing special.
Send those pics to Brewers instead of a asking bunch of people on this site, some in this hobby for 40+ years, that you don't trust or believe.
