bendix brake booster #2513550 need help to id

[yorks69machI]

I pulled the booster out of my 69 mach and called around to get a replacement, but no one could match up the number on my booster to anything in their catalog. The prev. owner may have switched them or bought something different but the present booster is a Bendix #2513550. If anyone can tell me if this was from a different car I would appreciate it.
Ed

 

[yorks69machI]

More info-- from looking on the web the number might be from a mercury of ford car in the later 70's. If anyone can find out or knows how I might find out please let me know.