Working on putting a '66 coronet back together. Nothing major at this point.

1) Who makes the best fitting carpet sets (I assume wagon will be the same as a 4-door...but not 100% sure)
2) Looking at aftermarket wheels since I converted to disc. Have had a couple of Moparts members give me their best shots, but wheels and tires? 15"? 16? Fitment options, i.e. backspacing and tire sizes? Thinking American Racing Torque Thrust II's, but lots of options for finish, spacing, size, etc.

just looking for some thoughts.

ACC's carpet fit well in my '63 wagon.
Not a lot of room in '66-'67 rear wheel wells, but lots of guys here own them; try the Archives here if you don't get enough info on this thread. If I remember correctly, you're probably limited to 7" wide, 4.5" BS, 255 or maybe 275 wide tire as far as off-the-shelf stuff. Height-wise, the front of the wheelwell (for fronts & rears) are the traditional Mopar tight spots. Rim diameter is pretty open depending on your brakes (big disc swap?) and the car's intended appearance.

A 255 will fit well for all-purpose use. Every 275/60/15 I have seen in the stock, unmodified wheel well rubs somewhere, at some point in it's use (i.e. more than two people in the car, etc.)

I'd definitely say 4.5" bs is the MAX before you start running into the leaf spring.

The other factor is that you will have to drop the rear end waaaay down to get the wheels off with a big tire. Not something you can do by the side of the road typically.

If you get creative I imagine you could get some pretty big wheels out back if the ride height wasn't too low and the inside wheel lip is folded over. The other option, if you want to run a taller tire is to use longer spring hangers and install sliders in place of the shackles for ease of relocation. This is how my stock '66 Charger has a 29.5x10.5 slick on it with un-cut wheel wells and a 68-69 width Dana.

Measure it up a bunch of times before your order to be sure. I was sweating it the first time I installed my custom ordred Weld 2.0's lol.