"Totally original" sounds like a really noble idea, until you start getting into the car to actually fix it. The fact is, there is no such place that has everything. No big dealer that has a sign, "ONLY ORIGINAL
PARTS HERE!" If you ever DO find such a place, you might need to be a billionaire to afford them.
There's such a thing as
NOS parts (new old stock). In other words, one day some Ford dealer decided to sell of the old
parts they will never use, and someone bought them and has been sitting on them. Of course as time goes by, fewer such
parts exist. Plus, certain
parts such a rubber hoses are no good -- gotta buy new. And then we have
parts you simply don't want. An example is valve seats; if you rebuild your engine you should replace them with hardened ones that handle unleaded gas. Air conditioning? Can't get R-12 anymore. I can go on and on.
Next, do you want to keep using the points and condenser, or
Pertronix ignition? Keep tinkering with timing and dwell, or fix it forever? Tires? Repro, or just put some radials on there? There's going to be a compromise somewhere, it's up to you to decide where to draw the line. Do you want a perfect trailer queen or a driver? If you plan to drive it, pamper yourself and do it right -- albeit not totally original.
Radio -- I'm using this as an example, not because of the business but due to my experience. I get constantly asked about "restoring the radio to original." I no longer offer it. Why? Simply because certain
parts are harder to find, some things have to be modified anyway, and the thing is obsolete when you're done. The only place to get IF transformers and
coils, is another radio that's just as old. Vibrators, there are
solid state versions but no longer original. Some dealers pull the rectifier tube and stick diodes in there, and bypass the electrolytic with modern ones under the chassis. There are plenty of other such tricks -- the set will work, but it's not original and it's not reliable -- and you only get AM stations. Conversion? Put a portable radio on the seat? It's up to you. I bring this up because the entire rest of the car is the same way.
Best thing is to step back and decide what you really want to do. Concours perfect? Driver? Resto-Mod? Ultimately YOU are the one to decide where to draw the line, remembering that originality is not always the practical way to go. Best to decide all of this before you start on yor project.
As for where to buy the
parts, get several catalogs, subscribe to Hemmings, watch for "parted out" specials, and have fun with your new hobby!
