Which style carpet and how does it compare between suppliers?

How does this sound?

1. Put down my own sound deadener.
2. I'll order the 500 series 80/20 loop, nothing special.
3. Let it sit in the sun, or use a heat dish contraption (my wife bought one to use in the mornings when its cold and didn't want to turn on the heater) to soften the carpet
4. Glue or Screw (where appropriate) the high spots of the carpet that don't sit proper to the deadener.

What after market floor consoles are available for a 65 dart gt? Do I need to have any specific provisions in place for one?

Sounds good. I used jute for backing but you could as well use Acoustamat or something like it.

The carpet comes folded and rolled in the box. It's a good idea to roll it out and just let it sit out for a while.

A hair drier (gun style) is a good heat source, too. You may want to have something like a hammer handle available to poke and prod the carpet into position while the heat is on. Tends to irritate the hands, otherwise.

You can do this. Good luck.

P.S. You can install the 66-76 console if you have all of the parts and can weld the mounts. The other is to get creative and design & build your own. You know something to hold your cell phone, cups/cans of beverages, or provide a home for your sound system and avoid cutting the dash. Your car, your call.