I know that this will ruffle a few feathers, but here goes:
It should be remembered that Carroll Shelby only dropped an engine into an existing car, the manufacturers of which were struggling to find a replacement for an engine which was no longer available.
Shelby`s team re-engineered some of the Cobra`s chassis,suspension & drivetrain to cope with the extra forces from the more powerful 260 & then 289 engines, and then came the change from 3" to 4" chassis tubes & independant suspension from transverse leafsprings.
The Chassis` & bodies were ALL supplied by AC, (apart from the Coupe bodies) so, in truth, the only truly original cars would be the ones made on the original Bucks, Formers & Jigs, regardless of the current name of the company.( I believe a few of the original employees from Thames Ditton are still involved in production...or at least were until recently.)
Carroll Shelby never made Chassis` & bodies, so the continuation CSX4000 & 7000 are effectively replicas,despite bearing the names Shelby & Cobra legitimately.(AC never 'owned' the rights to the name Cobra)Also, in theory,they shouldn`t have an 'X' in CSX, as this was AC Cars identification for 'export' cars to the USA.
OK, I`ve lit the fuse.....I`ll stand back now and wait for the Bang!