Any person who attempts to compile a list of the greatest cars of the 20th Century is sure to spark spirited debate. Some people will argue why a particular vehicle should be excluded, while others will provide sound arguments as to why others should be included. For me, the Citroën SM is a car that should make that list. This was a ground-breaking car in so many ways. While its styling might not be to everyone’s taste, there is no denying the fact that it is distinctive. This 1973 SM has been sitting for quite some time, and it will require a particular individual if it is to be returned to active duty once again. It is located in Pomona, California, and has been listed for sale here on eBay. Bidding currently sits at $2,275, and the reserve has been met.

The owner of the Citroën isn’t exactly forthcoming with information on the vehicle. We only receive a single photo of the vehicle’s exterior and no information on whether there are any rust problems. Reassuringly, the SM was not a car that was particularly prone to rust issues, and if it has spent the majority of its life in California, then that augers well. It appears that the driver’s side front fender has been unbolted at some point, but what can be seen of the rest of the body seems to be intact. The paint is looking quite oxidized, but it would be interesting to see how it would respond to some work with a high-quality polish. Thankfully, all of the tinted glass appears to be intact. It is all still available if needed, but various pieces can be quite expensive. The exterior styling of the SM could best be described as dramatic. It appeared in an era when cars were generally more “boxy” in shape. The teardrop shape of the Citroën allowed it to be aerodynamically efficient. Where many manufacturers struggled to reach a drag coefficient of 0.30, the SM managed to achieve an extraordinary 0.26. That meant that it required less engine power to achieve any given speed than its rivals. It also provided significant benefits in terms of fuel consumption.

The Citroën would have rolled off the production line equipped with a Maserati-developed 2,965cc V6 engine, which was coupled to a 5-speed manual transmission. This V6 would have been capable of allowing the SM to cover the ¼ mile in 16.5 seconds, and winding out to a top speed of 140mph. For such a relatively small engine, those figures are quite impressive. However, it appears that this car has received a transplant at some point. There is now a 4-cylinder engine occupying the space under the hood. The V6 could be prone to several issues if they weren’t maintained correctly. The most significant was the fact that the camshaft was chain-driven. The chain would stretch over time and required manual adjustment. If this work wasn’t performed, there was a real possibility that the V6 would produce some loud crunching noises as pistons and valves became intimately acquainted. I would suspect that this may have happened here. Hence, the transplant. It isn’t all doom and gloom, because a replacement V6 is included in the sale. It isn’t clear what sort of condition this is in, so an inspection will be required. If the buyer intends to slot this engine into the Citroën, there is one useful upgrade that they should probably make. There is a kit available that equips the timing chain with an automatic tensioner. If this engine isn’t fitted with one, then I would be rectifying it pretty quickly. The SM was also heavily loaded with technical innovations, and this is the main reason why I would advocate for it being included in a Top 100 list. The suspension was an upgraded form of the hydro-pneumatic, self-leveling suspension that was initially fitted to the DS model. This provides a motoring experience that can feel quite alien to the uninitiated. Tip the car into a corner at any speed, and it sits flat and firm, with bags of grip. However, that same taught suspension does an incredible job of absorbing lumps and bumps if the going gets tough. It also features variable-assist power steering. This not only isolates the wheel from the jiggling that would be experienced over rough roads but provides a situation where the V6’s 190hp can be fed through the front wheels with zero torque-steer. The steering is also extraordinarily direct and does take some adjusting to.

The interior of the Citroën is quite dirty, but it does appear to be free from significant problems. I can’t see any tears or appreciable wear on the leather seats, while the dash seems to be in good condition. The quirky touches continue inside the SM. After all, there aren’t that many cars that feature the radio mounted vertically next to the elbows of both front seat occupants. That makes it easy to reach but makes reading the radio dial reasonably awkward. It appears that the vehicle came equipped with air conditioning, but it isn’t clear whether the system has survived the engine transplant. Beyond the A/C, it comes equipped with the factory radio, along with power windows.

The Citroën SM is a car that isn’t to everybody’s taste. However, it is an engineering masterpiece. Like any masterpiece, it can command a pretty price when offered for sale. Pristine examples are capable of reaching $60,000 in the market today. This one has a long way to go to reach that sort of level. It is also an unknown quantity due to the lack of photos and information that the seller provides. One thing is for sure; Only 1,150 examples of the SM were sold in the US during 1973. That means that if you bought this car, it would be likely to be the only one in your street. Is that rarity enough to tempt you to follow-up on this classic?