Yes my foot box is about 13.5" across. The dead pedal, on mine, is actually more forward than the clutch pedal too, this has screw inserts from ERA to position it. The picture you have also shows the gas pedal bent differently. Mine actually comes down to the right of the intermediate shaft, not the left then bent over. The brake pedal was definitely bent towards the gas pedal. As for the foot room, it's tight but not bad. Kinda like a newer vette, kinda. But now looking at the pedals it's hard to tell. Maybe the measurement should be taken like Patrickt's as the foot box looks to be modified from the engine side. I think the cats out of the bag on which car this is.
I always wondered how they did all that. If it's the car I'm thinking of it's cool, trick, and one off. That might also be an issue too.
Got any "Mustang Stuff" next to the coin collection?
Regards, Matt