Authenticity reference

SD-455 cylinder-head identifiers

numbers matching · reported

1973 Pontiac Firebird Trans Am exterior in Cameo White/blue graphics; same-year Trans Am context, not individual-car SD-455 proof. 1973 Pontiac Firebird Trans Am SD-455

Reference Details

Common issue: Non-SD Pontiac heads installed on an engine represented as SD-455
Confidence: reported
Correct value: 16 casting number on the center exhaust ports with 6H stamped on the head pad
Where to check: Center exhaust ports and pad below the lower valve-cover bolts

Cars With This Authenticity Marker

1 linked car page.

1973 Pontiac

1973 Pontiac Firebird Trans Am SD-455

Factory Pontiac Firebird Trans Am with LS2 SD-455 option

Sources & Documentation

Hemmings Super Duty Firebirds by the Numbers