Classic Muscle
Search cars, engines, parts...

Search Classic Muscle

Enter at least two characters to search the archive.

Enter at least two characters to search the archive.

Authenticity reference

Engine identification number format and boss location

numbers matching · documented

Reference Details

Common issue
A replacement or restamped block represented as original without a factory-format 426 identification number at the documented boss location and supporting paperwork.
Confidence
documented
Correct value
Factory engine identification uses a two-letter plant code, three-digit cubic-inch displacement, four-digit date code, and four-digit daily sequence; the 426 entry is listed, with the identification boss located at the left side, front of block, below the cylinder head.
Where to check
Engine identification-number boss on the block, then reconcile the stamped format and date/sequence with factory paperwork for the specific car.

Cars With This Authenticity Marker

1 linked car page.

Sources & Documentation