For the record, there were two varieties of the Shelby Cobra.
The first one was a modified AC Ace with a Ford small-block (260/289) V-8 stuffed into it, replacing the previous L-6.
This was the Mark I. It had an ancient transverse-leaf suspension on both ends and a recirculating-ball steering system. After 75 were produced, the 260 engine was replaced with a 289 (same block). 51 Mark Is with the 289 were produced.
Starting with the 127th car, the steering was changed to a rack-and-pinion design. This was the Mark II, of which some 528 were built.
The Mark III, which is what nearly all replica Cobras are built to look like, was much different. It had a coil-spring suspension at both ends, redesigned, heavier, stiffer chassis, and modified bodywork (the fender flares and the vents behind the front wheel openings are the easy giveaways), plus a big-block 427 V8 engine. This one would do 185 mph in competition tune.
Only 56 of the planned 100 competition models were produced, and Shelby did not get it homologated for racing at the time. Of those 56, only 25 were sold as racers. The other 31 were detuned and fitted with windscreens, and sold called "S/C" (for semi-competition) models.
There were 250 Mark III production models. Some of the later ones had 428 engines, cheaper, with longer stroke and smaller bore, than the 427.
Replicas of this are what we see on the streets. However, very few of them have big-block engines in them, much less 427s. Most have either small-block 302 V8s or tall-deck small-block 351 V8s in them.
