[Jerry H.]

You are going to find a lot of conflicting info on this subject, and going to look at a lot of restored cars with a lot of different markings. With that being said, I can state this, I've owned and looked at several unrestored, untouched and low mileage 65 GTO's since 1979 when I did my first restoration. I owned my first one in 1969. There were very few actual marking on these cars that you can see. There are a couple of 'shift' stamps that can be seen on the firewall when you take the fenders off. Most of the firewall markings were made and then painted over with the semi gloss black paint; but you could see or feel the impression of those markings under the paint. The most common of those markings on the firewall are the exterior, top, and interior color designations. The '337' you saw would be the code of the interior. A one letter code for lower exterior color and letter (or number if vinyl or convertible top) code for the top. Example: AA would be Starlight Black bottom and top. A-2 would be Starlight bottom and black vinyl or convertible top.

As far as the undercarriage, the driveshaft has a 2 line painted code, the rear end pumpkin has a splash of paint on the bottom next to the pinion designating the axle ratio, the steering box has a spot of paint on the top of it, and there are probably some other splashes of paint that would represent when a certain bolt or part had been properly torqued, but I haven't seen any documentation as to when and where those would go. I've just sure seen a lot of cars with that on there!

You'll probably run across some cars with some 'part number' stickers on parts like springs, sway bars, etc., but I'll bet these didn't last past the first puddle or rain shower.