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Vintage Auto Glass CodesCracking the codes of vintage Chevy glass
It should be no secret to anyone reading this article that it's possible to nail down the casting numbers and date code sequences on just about everything found on a vintage car, GM-built or otherwise. Included in the mix are cylinder blocks, heads, starters, water pumps, alternators, intake manifolds, rear axle housings, transmission cases, and so forth. The sky is pretty much the limit once you really start to dig. You can even nail down date codes on interior trim panels (not that anyone would see them), jacks, and even tires. Vintage auto glass codes are no exception. "Numbers matching" also applies to factory-installed window glass.
If you examine a piece of unmolested, genuine (old) Chevy auto glass carefully, you'll find a set of white characters printed on the glass. These characters are, in most cases, printed to read from the inside out, so they'll read backwards from the outside of the vehicle. Typically, they're found near an edge of the glass. A good example is the quarter glass: It has the characters near the lower corner close to the vertical weather-strip. The rear glass code is the exception: It will often be in the lower center of the back window. Corvettes are another exception; they do not have the characters presented as a mirror image (you can read them from the outside), but they're beyond the scope of this article.
So far so good, but what's up with the characters? They include the glass code, which determines the month and year the glass was produced, as well as other specifications. Using Chevrolet as the example, the vast majority of musclecar-era vehicles featured glass manufactured by a company called L-O-F. These initials signify Libby-Owens-Ford (Ford Motor Company was a partner). A secondary source was PPG or Pittsburgh Plate Glass. PPG was more often found on other GM lines rather than Chevrolet models. According to the National Corvette Restorers Society, vendors other than Libby-Owens Ford producing OEM glass in Chevy Corvettes from 1963 to 1972 is unlikely.
OEM glass was called "Safety Plate" or "Safety Flo-Lite," while replacement glass was commonly called "Safety Float" (you'll often find Safety Plate in earlier cars and Flo-Lite in later cars). "Float" and "Plate" refer to the glass manufacturing process. "Float" glass eventually replaced "Plate" glass in the manufacturing process (it was a cheaper, and perhaps more efficient manufacturing method). In any case, each piece of glass indicates the type within the code.
All glass except the windshield will be solid tempered. Tempering is, for lack of a better term, a thermal process the glass goes through after manufacture. Essentially, this process creates a more durable product. The windshield differs in that it is manufactured from laminated glass. Here, the glass is manufactured by sandwiching a core of robust transparent plastic with sheets of equally robust annealed glass. The term "Soft Ray" was used in tinted glass applications. You'll also find the word "SHADED" printed across the top of the characters in most tinted glass windshields.
The characters on the glass regularly includes "AS" followed by either a "-1" or "-2". The characters "AS" stands for "Americans Standards Association of Classification". Windshields carried the "-1" suffix while side and rear glass included the "-2" suffix. The difference is obviously due to the fact windshields are manufactured from laminated glass.
The breakdown for 1967 and prior model year glass codes is as follows:
1968 and later model glass codes are as follows (they're close to the earlier codes, but they carry the DOT marking):
Soft Ray: tinted glass; Safety Plate: original equipment glass; Safety Flo-Lite: original equipment glass; L-O-F: Libby-Owens-Ford; AS2: side glass; Solid Tempered (or Laminated): glass type; V: 1969 calendar year; A: month of September; DOT 15: Department of Transportation rating code; MXX: manufacturer's model number.
The auto glass codes that follow depict L-O-F year codes for 1963 to 1972 vehicles. Don't confuse vehicle model year with the glass date codes. The glass was coded for the calendar year of production, not the model year. For example, something like a 1966 Chevy II could easily have been fitted with glass bearing a 1965 code.
Month codes are equally simple; they break down as follows: