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NOS, OEM, or Replica Parts? Which Are The Best Classic Car Components For Your Project

When restoring a classic car, no matter how old or what type of vehicle it might be, you're going to have a number of different options when choosing replacement parts. In fact, it can often be confusing to try to work through all of the choices available to you and decide which ones are the best match for the spirit (and budget) of your project.

One thing to keep in mind is that there's always a chance you'll be able to order brand new factory parts that still fit your classic, particularly if it shares its lineage with an existing model. For example, when searching for flywheel bolts for my first-generation Datsun I discovered that Nissan has used the same part on every single manual transmission car it has ever built—including the modern Z. One quick trip to the dealership and I had all the bolts I needed.

Chevrolet Bel Air rear quarter

If you can't locate what you need from the factory, there are a number of different tiers when it comes to restoration parts, which come with varying degrees of quality, cost, and availability. Understanding what each type of replacement component has to offer will help you make the right decision when ordering the parts you need.

New Old Stock (NOS)

Despite what the Fast and Furious franchise might have you believe, NOS doesn't just stand for the popular Nitrous Oxide Systems power adder. In the classic car world, NOS more often refers to 'New Old Stock' replacement parts.

What exactly does that mean? The origin of New Old Stock is a little convoluted: it describes official OEM parts that were ordered as 'new' back in the era in which the vehicle was in service. For whatever reason, these parts then sat on the shelf for years and years, never having been installed or used in a repair.

International Harvester Scout with silos

For many collectors, NOS parts are among the most desirable to use during a restoration. This is because they almost always offer the best combination of fit and function, given that they were designed and produced using the same tooling as the car or truck they will be installed in. Even if a third party supplier built the part in question, it was accomplished using the standards of the era.

NOS parts are a little like opening a time machine to the year your vehicle was built and stepping right into the service department. As such, they often command a price premium, and finding them sometimes requires a bit of luck (as certain items can be rare), as well as a willingness to spend more cash that you might have expected.

Datsun L28 engine

A word of warning. Not all materials age well on the shelf, particularly rubber, nylon and plastic, which can dry up or become stiff and brittle with time. Keep this in mind when looking at NOS parts that make use of rubber seals or soft-touch interior components.

OEM Replacement Parts

In some ways, OEM replacement parts are the next-best thing to NOS. These are parts that have been licensed by an automaker to be manufactured by a third-party supplier to fit in the vehicle you are restoring, and as such they come with all of the usual guarantees and protections that you'd find with a factory part.

That being said, OEM parts come with a few caveats. Car companies will often change suppliers for the same part several times of a period of years, which means components can change slightly in terms of shape, size, functionality, quality and reliability by the time they make it to the modern parts counter. There's a chance that whatever you order won't be a perfect fit for your project, and you may need to make modifications to use the part in question.

Porsche 911 front end

It's also true that OEM suppliers aren't in the habit of building parts that nobody wants to buy. If you own an unusual or rare vehicle, or are looking for a part that wasn't shared with many other models, you may not be able to order an OEM replacement part.


NORS parts are an unusual niche that walks the line between New Old Stock and OEM. 'New Old Replacement Stock' can be thought of as period-correct replacement parts, and are often branded by their manufacturer instead of the automaker.

Nitto tire on C10 pickup

They aren't quite OEM, but they would have been installed by a dealer for repairs done on a vehicle if no OEM parts were available at that time. They don't hold nearly the same cachet with collectors as NOS, and as such won't feature the same high pricing.

Replica/Reproduction/Remanufactured Parts

If NOS parts are a little too expensive and you can't find the OEM replacements you are looking for, then it's time to broaden your search to include the wild, wild west of replicas, reproductions and remanufactured parts.

Replica and reproduction parts are just what they sound like: the efforts of third-party companies to produce components that match the factory, only without all of pesky costs associated with licensing. Sometimes called 'jobber' parts, due to their popularity with budget body shops and mechanics, they will get the 'job' done, but often times have trouble matching genuine gear when it comes to fit or quality.

Scout with old tractor

That being said, there are also companies out there making high-end reproductions of parts for cars that have almost no support from either the aftermarket or the factory. Navigating the world of replicas means doing your due diligence on who is reputable and who isn't before making a purchase.

Remanufactured parts will be familiar to almost anyone who's worked on a project car. These components are refurbished versions of used parts that have been rebuilt to work like new. They come with a guarantee, and almost always require a core exchange where you send the seller the component you are replacing. They can be a very cost-effective way to repair expensive mechanical parts if you're not concerned with originality.

Used Parts

Wait, used parts in a restoration? For some projects, picking up a parts car to pick clean can often be the most cost-effective way to get a vehicle back on the road. Some items, such as trim pieces, fasteners, electrical components, and interior details can be very difficult to source any other way. The same goes for sheet metal, especially if originality is important to you.

Chevrolet Belair interior

Tapping in used parts to complete a project is never a bad idea, provided that they're in good condition and won't simply put you back at square one a few miles down the road. They're also often an affordable alternative to NOS or OEM components, particularly on more modern classics.

Looking for more restoration tips? Check out this master class from Shelby expert Tim Lea.

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