Congratulations on getting a new project car. Sorry to say, you will never really know how common or rare the option combinations were back then. They didn't keep great records. By 1973, the cars weren't selling as well and the options were fewer than the earlier years. I'm not sure what makes you think it was a special order car, and I don't know what you mean "if this is a black car the rallye would have been red correct?". A simple answer for you is do what you want with the car that makes you happy when you are all finished. Not that 1973 isn't a great car, but it's not a valuable car. If you are missing the original motor and trans, it will never be numbers matching so go have fun with a custom build.I know this has been discussed before but I wanted to know what people thought about my specific car.
One other question is if this is a black car the rallye would have been red correct? But what about the V6X Black Longitude Sports Strip? They put that on a black car?
The A6XW interior was a vinyl material, white seat inserts, white bolster, black carpet, black shelf and instrument panels, black steering wheel, white headlining and door panels. The flat black V6X body stripe tape was available on any exterior paint color. Flat black stripe on a gloss black body was possible.
If you have the money, time, and ability, I vote you find any size motor you want (either modern or old school whatever), add some modern brakes, steering, suspension, tranny, go nuts, have fun, drive the daylights out of it, and don't worry about it being rare/collectible/valuable whatever. Make it your own. You know they make fuel injection carburetors that look old school but work like modern fuel injection. Put it on an old school type motor and get modern performance with an original look.
Check out this website: The 1970 Hamtramck Registry Home Page go to the LIBRARY page to see option books from 1973, read up on other pages and the links from there to see some of the historical stuff. And don't for get Classic Industries for ordering new parts. They have most everything you need. Please post pictures of the project as you go along and keep asking questions. Have fun!!!