I dont think there is enough width there- there certainly would not be with mine, without screwing up the "headroom".
This is all a geometry/space usage problem. Other thoughts/options that I have used or thought about using:
1) I modified the seat. I took a oval shaped chunk out where the lower part of the seat back hits the wheel tub. Then, i put a new chunk of aluminum back on the seat. that new chunk is basically a reverse of what was there before, its a forward dimple, instead of a indented dimple. You actually dont even notice it if you do it right, the dimple fits inbetween your hip bone and ribs (kidney area??) but you gain about 2" legroom, and also room to tilt the seat back more.
2) tilt the seat back with wedges under the seat: high at the front of the seat (duh). The back of the seat ends up bolted directly to the floor. This mod drops your head down = more headroom. What it also does is pull your feet back, effectively giving you more legroom: to prove this to yourself, sit upright in a tilting chair. Put feet on the ground. lean back. Knees go up, feet move back. Be careful you dont end up with knees bashing ther bottom of the steering wheel (although then you raise the steering wheel a bit, ask me how i figured that out...)
3) take the seat cover off and shave a bunch of seat foam out. Mine is still surprisingly comfortable if you sculpt the foam to fit your ass cheeks
. I shaved both the seat area and the back, which gained me both head and legroom. Do it in stages! easier to take out than put back
There are fancy kits you can buy that allow a 100% custom foam arrangement, you pour the foam into a bag you are sitting on or something like that, the foam expands around your body for a perfect custom fit. I'm not allowed to use the crack filling foam around our house any more so i dont think this would go well for me.
4) haven't done it yet on mine, but I could move the whole pedal assembly forward probably 2-3" as full travel on the pedals at the moment ends up at least 3" from the firewall. I'd box out where the current pedal arrangement bolts to the engine side of the firewall.
5) very significant mod option: John Chestnut on this site made a custom cobra where the footbox was SUPER long, and the headers actually went up and over the footbox then down and out. So, now your feet can go all the way to the front wheel tub. Probably 6-8" on most cobras if you look at it.
6) not quite as significant mod option: take your existing headers, and the 4 separate exhaust pipes that are basically in a square shape (2 above 2) that sit in front of the footbox, between the footbox and the front wheel tub: re-route the two closest to the footbox to on top/underneath the other two, so you end up with the 4 pipes stacked vertically before the collector. Think this shape:
O
O
O
O
Instead of this shape:
OO
OO
This will allow you to extend the footbox at least by the diameter of the exhaust pipes (likely an easy 3"). Keeps the same collector location likely.
7) for a spouse, you could rig up a sliding pedal scenario instead of a sliding seat.
Hope this gets the ideas flowing for people.