I can't tell you what it means, but my 40,000 original mile 1967 Chevelle was built in Oshawa and it also says C2 on the firewall! Mine is written in grease pencil just below the rubber wire retainer on the firewall. I know it has not been touched as it was bought new by my late aunt.

By any chance do you know when your Beaumont was built? My Chevelle rolled down the line starting the 2nd shift, 12-13-66 and rolled off the line completed on 12-15-66. My engine was built 12-12-66 in St. Catherines and so far has never been removed. It is coming out this year for the first time.

Below is a picture of my untouched firewall before cleaning. Back around 1982 my aunt blew a rear brake line while decending the Wentworth Street mountain access in Hamilton. Thank God it was a '67 with the dual reservoir master cylinder and not a '66! The buffoon who replaced the brake line spilled brake fluid on the firewall and never cleaned it up (who cares if it lifts paint and allows rust to start? Nice attitude!)