Can anyone tell me what the numbers and letters mean that are stamped on the firewall of my 71 442 conv? I have a Y with a square around stamped in blue and an A-4 stamped in yellow ink.

 

i always wondered myself. i seen somewhere that they are making this stamp for people to restore there car and have the stamp there.

 

I have several of these on my 72; I am thinking they are QA stamps that certain line workers stamped on the firewall when either their jobs were complete or inspections were complete and passing. Some are neat stamps, some are scribbles. Special (costly) crayons are sold for repro scribble applications.

 

another marking i have seen is on 72 442 W-30s. on 2 of these cars i have seen with the original engine paint had an X marked on the driverside front valve cover. a hand drawn X