The Chrysler fender tag is a small aluminum or steel plate, typically two screws or rivets, riveted to the radiator support or driver-side inner fender on B/E/A-body cars from approximately 1965 through 1974. Where the broadcast sheet carries the line-side production data — engine letter, plant code, sequential build — the fender tag carries SALES codes: option packages, dealer-installed equipment, and the cosmetic / trim spec that distinguishes a Charger R/T from a Charger 500.
The vocabularies are different. A 1970 broadcast ENGINE cell shows 'V' for the 440 Six-Pack; a 1970 fender tag shows 'A12' (the package code) plus 'E87' (the sales code for the 440 Six-Pack engine option). A12 means lift-off-hood induction package, not anything specific to engine displacement. Reading a fender tag without knowing it speaks a different language than the broadcast sheet is a common decoding error — Plenum keeps the two vocabularies separate.
Fender tag layout: 5–6 rows of 4–6 codes each, embossed in raised aluminum lettering, read bottom-to-top and left-to-right by convention. The bottom row is the closest to the broadcast VIN row — body code, engine sales code, sequential build. The middle rows enumerate option packages (R11 AM radio, V21 hood paint, A14 power steering, etc.). The top row often carries 'END' as a terminator. Lynch Road tags are notorious for omitting the A34 Super Track Pak callout even when the car was built with the 4.10 Dana 60 — a plant-correct silence that's not an error.
Plenum's fender-tag schema family ships in v0.3 — one schema per year, 1968 through 1974, sharing a single SALES-code vocabulary (since SALES codes were largely stable across the era, unlike broadcast engine letters which changed every year). The vocabulary covers A-series axle/package codes (A12, A33, A34, A36, A53), B-series brake codes (B41, B51), C-series interior (C16, C55), D-series transmission SALES (D21, D31, D32), E-series engine SALES (E55, E61, E63, E68, E74, E85, E86, E87), the full M-series mouldings, R-series radios, V-series stripes/vinyl roof codes, and the literal 'END' terminator. The decode engine cross-walks the fender-tag engine SALES code against the VIN engine letter — they name the same engine in different languages, and a mismatch flags as 'possible misread or replaced tag'.