An r code with the right height slicks, or a gear change, on slicks will run low 11's and even in the 10's.
Back in the day MM&FF ran a vert with slicks with a height compensating for lack of gear and it went 11.30.
Which in a hardtop would be 10's.
Keep in mind the times you see are listed for the s351 are standard radial times, s197 cars are undoubtably on drag radials or slicks.
120mph+ is fast as hell off the showroom floor.
Saleen supercharged s197s barely make it to 115mph in the quarter.
On equal tires, the s351 would spank it without breaking a sweat.
Very very few cars run 11's off the showroom floor on regular tires, that's why you have to look at the mph to see what is really faster.
New z06 runs high 11's, equivalent to the s197's you quote, but it's at 126mph on std radials, guys have gotten them low 10's on slicks and drag radials.