57 Merc data decode and identification

[AnnRenee]

Hey all!
Just bought what was supposed to be a 1957 Mercury Montclair...but research has me questioning if it's really a Monterey...and unfortunately Merc's are a new interest for me and the info out there leaves something to be desired.

I have found the data decodes for a '56 and for a '58 and the same number comes back as different models ..Why? Could they make it more confusing and did Mercury really make the 64A a different model depending on year?

What are the obvious differences between the Montclair and Monterey?

And lastly, how to determine if your y-block is a Ford or Lincoln version?

I have attached my data plate and so if anybody could help, it would be appreciated. I'm really excited for this new project!!!