I'm close to 6'6" and 320 lbs with a size 16 shoe. I made some basic mods to my FFR MKIII and I fit fine. As Mark mentioned, like a glove, but it's comfortable. Basic mods are:
Kirkey Vintage seats. Mine are in a u-shaped bracket that tilts it ever so slightly forward, bolted to the floor. This adds 2" to both verticle and horizontal legroom. I also have Wilwood adjustable pedals, which add 2" more. EDIT: I called FFR and confirmed that adjustable Wilwood pedals are part of the MKIV kit now, not an aftermarket item as in my car. /EDIT I have a 350 HP BOSS 302 in my car and that allows me to use a inner footbox wall that is straight instead of bent. Also, for my big feet, I cut out the crash bar on the left side of the footbox. The FFR MKIV has a different radious on the bar now and If I had a MKIV I wouldn't have had to cut it out.
With these mods I can fit just fine, and didn't have to resort to a stretched wheelbase. As a matter of fact i fit better in my car than I did in a 96" wheelbase car I tried on at a get together once...
HTH,
