There has already been at least one low 12 that I've seen timeslips for. 12.3@118mph in stock trim by a Viper owner who picked a coupe and a vert up.
I would imagine anybody worth a crap at driving is gonna pull a mid 12 out of the car. It would be a low 12 car had they not used the iron block.
The late 60s muscle doesn't stand a chance against the new Cobra. Not even close. The quickest of the quick might have been able to rip off a low 12 with today's street tires at maybe 105-108mph.
The Boss 429 was just too front end heavy to get a good launch on street tires. The best bet to outrun a new Cobra is the 1968 428CJ. The best time I've ever seen listed was a 13.56@108mph. It was tested by Kar Kraft magazine. Of all time Mustang's, the 1968 GT500 with the 427 may have an outside shot of running near it, tuned by the professionals at Shelby American. Nobody can really vouch for how powerful that engine truely is. It was so rare (I have one
) and there are so many stories surrounding it, that it's hard to tell.
The 1968 GT500 with the 427 was rated at 390hp@5600rpm, and 460lb/ft@3200rpm. The 427FE was the most aggressive engine Ford ever shoehorned into a production car. My version, like the GT500's was the weak low riser setup. The 10.9:1 CR on the Shelby is much less than the 12.0:1 my 1963 version has.