I've had a couple of people ask me this question. The easiest way to get pictures out is right here. So, here goes:
Throttle 01: I circled the two bolt that the plate is attached to the car. These are two of the four studs that come off of the back of the brake booster. Remove those nuts with a 13mm socket.
Throttle 02: You can see where the studs go. The top one is slotted because it has slide up in to place. Because of the brake/clutch pivot bar, it won’t go straight in.
Throttle 03: This is the secret. Now it all makes sense. These are called Surface Mount Nuts, and they come in a variety of configurations. I get most of my hardware from McMaster.
https://www.mcmaster.com/nuts/surface-mount-nuts/ You can weld or glue them in place, but it’s not really necessary.
Throttle 04: You can see how the 5/16” surface nuts fit up in to the base of the pedal. These are 5/16” instead of 8mm because metric nuts are hard to come by. A 13mm socket fits on a 5/16 bolt pretty well.
I also pointed to this piece of plastic. It makes more sense in the next picture.
The bracket is an odd shape because it's made it out of a scrap piece I had lying around.
Throttle 05: The stock Mustang bracket has three mounting holes. The third one is on the right. But that makes the bracket too wide for a comfortable fit. The right side of the bracket flat cut even with the sensor body, so the assembly sits flush against the trans tunnel. Then I attached it to base of the bracket to make it a three legged mount. That small screw is to hold it together while the two ton epoxy dried. You can see I also trimmed the boss down a bit to make it sit flat.
Throttle 06: Here it is loosely assembled. The nuts fit up in to the holes in the plastic base so it can’t wiggle around.
Throttle 07: Loosely assembled, from another angle.
Throttle 08: Tight, and ready to install.
Throttle 09: Now you can see why the top hole in the bracket needs to be a slot.