Seed file — full Archetype C buildout deferred to Phase 1. Style notes for the Writer are thin; user/co-worker domain knowledge should augment before this file is loaded as authoritative Writer context.
The Mark I Cobras are the earliest production Shelby Cobras, built between January 1962 and the rack-and-pinion transition in the mid-1960s. They began with a 260 cubic inch Ford V8 (the prototype, CSX2000, in January 1962) and standardized on the 289 cubic inch V8 in 1963. The Mark I uses worm-and-sector steering and the original leaded-frame AC chassis adapted for the Shelby program. These are the first cars from a program that produced approximately 1,000 Cobras total between 1962 and 1967.
Production span and totals
- Prototype: CSX2000, built January 1962, originally fitted with a 260 ci Ford V8
- Production start: 1962, with the 260 ci engine
- 289 standardization: 1963 (the 260 was replaced by the 289 ci V8 as the production engine)
- End of MkI: transitioned to MkII (rack-and-pinion) configuration during the mid-1960s
- Total program production: approximately 1,000 Cobras of all types between 1962 and 1967. The MkI / MkII split within that total is not stated in current cited sources.
Defining mechanical characteristics
- Engine: Ford small-block V8, originally 260 ci, later 289 ci
- Steering: worm-and-sector (the defining mechanical change between MkI and MkII was the switch to rack-and-pinion)
- Frame: leaded AC chassis adapted for Shelby — the original AC Ace platform with reinforcement for the V8
- Body: hand-formed aluminum panels over a steel ladder frame, in the AC tradition
Variants
- 260 prototype era (1962): cars built with the 260 ci engine
- 289 production (1963 onward): the 289 became the standard engine and powered the bulk of MkI production
- FIA / competition cars: some MkI chassis were built or modified for FIA-spec competition
Sub-variant detail to be filled in during Phase 1 from cited sources (SAAC registry, period documentation).
How to identify
- Chassis number prefix: CSX, in the early portion of the CSX2000-onward range
- Worm-and-sector steering is the primary mechanical tell distinguishing MkI from MkII
- Engine identification: 260 cars are pre-1963 (very few); 289 is the production engine
- Body details vary between early and late MkI production (specific differences to be documented from period sources)
Exact chassis number sub-ranges for the MkI / MkII split to be confirmed from SAAC registry data during Phase 1 buildout.
Notable chassis numbers
- CSX2000 — the prototype. First Shelby Cobra ever built. January 1962. 260 ci V8 originally.
Additional notable chassis numbers to be added as build articles for specific cars are written.
Sources
- Cobra Authority buyer’s guide: https://cobra-authority.com/shelby-cobra-a-buyers-guide-to-originals-kits-replicas-tributes-continuation-cars/
- Cobra Authority AC history article: https://cobra-authority.com/the-history-of-ac-cars-and-the-birth-of-the-shelby-cobra/
- SAAC (Shelby American Automobile Club) registry — the authoritative source for chassis-specific provenance and configuration. Not always publicly accessible but is the source of truth for any specific-car claim.
Last reviewed: May 16, 2026