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Giving a vintage car a modern heart transplant is a common sight in the restomod world. And as crate electric motors become available, some classic cars aren’t just getting engine swaps, but EV swaps, too. However, while modern engine swaps have their upsides, they do have some drawbacks. Chief among them is the chance that your engine-swapped classic car’s value could take a dive. But is that a genuine possibility, or a pointless worry?

‘Numbers matching’ classic cars often have the highest market values

Speedkore's carbon-fiber classic 1970 Dodge Challenger 'Evolutuion' with a Demon 6.2-liter supercharged V8 engine swap
Speedkore’s classic 1970 Dodge Challenger ‘Evolutuion’ with a Demon 6.2-liter supercharged V8 engine swap | Speedkore

Originality is often paramount in the classic car market, at least where value is concerned. It’s part of the reason why that Ford Falcon XA GTHO sold for roughly $1.5 million, for example. And unless the car has its original engine, it can’t be a ‘numbers matching’ classic.

The term ‘numbers matching’ refers to the factory serial numbers stamped on various parts of the car, Hagerty explains. On a ‘numbers matching’ classic car, the numbers on the engine, body, and rear axle are all identical. And often, it’s these kinds of vintage machines that command the highest prices at auctions. Matching numbers can sometimes even overcome undesirable color combinations, Hagerty notes.

Considering that more automakers are making modern reproductions of classic engines these days, the idea of a single number plate can affect a car’s value might seem odd. And to be fair, it doesn’t always. For instance, the 1957 BMW 507 Series II that sold on Bring a Trailer last year for almost $2 million didn’t have its original engine. Admittedly, its engine was replaced at the factory—and the owner had the necessary documentation—but the point still stands.

However, when it comes to truly high-dollar classic cars, engine swaps can make or break fortunes. It’s why vintage Ferraris race not with their original engines, but with ones made by a company like GTO Engineering. Repairing a damaged classic car’s body might be expensive, but these cars are insured. Yet the risk of having to throw out an original Ferrari V12, or something with a similar pedigree, is simply too great to chance.

Plus, sometimes the original engine is the entire reason why a specific car is valuable. Case in point, the Chrysler Turbine cars. That’s definitely one classic car that loses value with an engine swap.

Modern engine (and EV) swaps can make some classic cars more drivable, though, and sometimes more valuable

Still, a modern engine swap doesn’t always lower a classic car’s value. Depending on the car and engine in question, it may actually raise its market value. But arguably, more importantly, engine swaps, as well as electric swaps, often make vintage cars easier to drive and live with.

That last part is a common reason why classic car owners perform engine swaps, DrivingLine says. Modern engines are more reliable, require less frequent maintenance, and produce more power for a given capacity. Also, not every classic car community is well-supported by replacement parts. If maintaining a vintage engine simply isn’t financially feasible, swapping in a modern replacement at least keeps the car going. And, in the case of something like an EV-swapped vintage Land Rover, it also removes a significant emissions source.

True, not every engine swap is appreciated in all classic car communities. But it’s not like the concept is exactly new. For instance, some Sunbeam Alpine owners swapped their roadsters’ four-cylinders for V8s to get Tiger performance without buying Tigers. These ‘Algers’ aren’t as valuable as original Tigers, but they are worth more than standard Alpines. And there are plenty of other classic cars that genuinely benefit from engine swaps, Car and Driver muses. Not just in terms of performance, but market value, too.

Should you put a modern engine in a vintage car, then?

A yellow classic Citroen 2CV with its original engine swapped for an electric motor
A classic Citroen 2CV with its original engine swapped for an electric motor | CLEMENT MAHOUDEAU/AFP via Getty Images

Check Out These California-Legal Engine Swaps That Are Impervious to Cops

Ultimately, whether or not a modern engine swap impacts a classic car’s market value depends on the specific car and swap. Putting an LS V8 into a vintage Chevy pickup? No problems here. Doing the same to a Lamborghini Miura, though, is tantamount to sacrilege for some, and will cause its value to tank.

Engine swaps don’t have to be permanent, though. Aston Martin and Jaguar, for example, claim their classic electric conversions can be reversed, MotorTrend reports. And reversible modifications don’t necessarily harm resale value, Hagerty points out. So, if you install a modern engine for your own enjoyment, but keep the original around, you can theoretically sell your car without losing a significant amount of money.

Still, at the end of the day, it’s your car. You don’t have to swap out your classic car’s original engine if you don’t want to. But cars are meant to be driven and do poorly when they’re not. And if putting a modern engine in your vintage car means you spend more time on the road, those sensations are worth more than just money.

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