Deciphering the Parts Code

Determining the heritage of your car’s parts is a sometimes confusing, but very important, task. What you install will directly affect your classic’s value, performance and score in judged events. Because a single part could potentially have a great impact on your vehicle as a whole, it is important to understand what you are purchasing.

The New Old Stock, or NOS, designation indicates that a part was produced as a spare or replacement part by the original manufacturer (GM, Ford, Mopar). The fact that it is a new, original part does not mean that it’s perfect. These parts were made 30-plus years ago, so some shelf wear can exist. However, NOS parts can be considered “stock” production components, and if chosen correctly, they will fit and function as well as the broken or missing parts being replaced. These parts are your best bet for concours style restorations, but are also the most expensive option.

The New Old Replacement Stock, or NORS, designation indicates that the part is a new “replacement” part, produced by companies such as Auto-Lite, Fram, or Champion. The production of these parts most likely coincided with the production of original factory parts. Sometimes, these parts were made by the same company as manufacturer-branded parts, but were marketed under another name.

These parts will function properly, but the fit may not be as good as NOS parts, and their markings may be different. Sometimes NORS parts are a “will fit,” meaning that they can be used with more versatility than original manufacturer parts. These parts offer a good value, but if you plan on entering your classic in a concours event, be aware that judges may deduct points for NORS parts.

Reproduction Parts are parts made by an independent company after the original manufacturer has ceased its production. They are becoming more popular as NOS or NORS parts are increasingly harder to find.

The reproduction parts market is large, but limited. These parts are usually produced for more common classics like Mustangs, early 50s Chevys and Fords, and muscle-car era classics (just try to find a reproduction part for a 1928 Whippet). Reproduction parts can also be found for the Ford Model A and Model T, but are most commonly used on “drivers” versus concours-quality vehicles.

All reproductions are not created equally, and must be chosen with care. Many are soundly produced, but others are cheaply manufactured at the expense of quality and fit. You get what you pay for, so if the price seems too good to be true, it probably is.

Quality used parts can be a very good option for the smart restoration enthusiast. They are typically original factory pieces, so they fit very well. However, much depends on the condition of the used parts. Many have spent years in a salvage yard where they have become weathered beyond repair. It is best to look for used parts that have been removed early in the life of the auto and stored inside. Mechanical parts may need to be rebuilt, but this is sometimes true with NOS parts also.

Quality used classic parts represent the best value for the restorer, as they are usually the least expensive option. Since they are original parts, your classic won’t be penalized in a judged event.

When it comes to parts for your restoration project, as with any important purchase, do your homework and know what you’re buying. The questions you ask now could save you a lot of time, money, and sweat down the road.

This piece is by Brett Gourdie of Bay Classics, a quality used parts, NOS, and NORS vendor.

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