The art of chassis stiffening was proven at the Revival circa 2003/4/5 when a few Cobras began to be....modified, shall we say....and the lap times of those one or two cars over a (not-so-modified) standard-spec Cobra was notable, by several seconds per lap. The owner of 39PH, a race driver of considerable experience, was a little amazed when a similar car went hurtling past on the outside of a corner, front wheel about six inches clear of the deck. He then realised it was not a level playing field.
If you trawl through the period Shelby American files of Dave Friedman, very few photos show a front wheel off the deck, other than the first race Cobra that was twisting itself into knots! Those were the days before sleeved chassis..