6 73517 006414     1st digit  year (1966) next 5 are model number  and last 6 sequence of production 



73517 Beaumont Custom 6 cyl Two door hardtop

The 3517 will tell you that it is a six cylinder custom hardtop.  (899 produced)

Gibby
The info from the data tag will tell you a lot more. Post it and we'll decipher the numbers for you. Better still take a pic and post the pic.
Hell, take lots of pics of the car from all angles, inside and out, under the hood, in the truck etc and post them. We love pictures. ( pics will get our attention and help pass the cold nights when we can't get out to the garage to work on our cars )
Ted