Starting life as a 360R

Sunday, Aug 02, 2026 · 1019 words · approx 3 mins to read

One reasonably common thing you’ll see if you’re looking to buy a Seven is cars that have been on an upgrade journey of some sort, starting out life as one particular model and specification before the customisation and upgrade bug takes hold. It’s one of the very appealing things to me about Sevens, and the factory often gets involved in the process.

Even if Caterham haven’t been the maintenance custodian of a particular Seven after they built and sold it, and even if the factory never built the car to start with, they’ll assess any Seven and its current state and upgrade it on the customer’s behalf. Not every upgrade is trivial and not every upgrade makes financial sense, but most things are possible.

My car’s been on that particular journey, starting its life as a 360R and was then upgraded to 420R spec before it was bought by the owner before me. Caterham built and sold the car as a 360R in early 2017, its very first owner using the Caterham Signature personalisation program to make a couple of non-standard changes to the normal 360R specification.

It was then upgraded to 420R specification in 2021, most likely by Oakmere Motor Group, a Caterham dealership (among other marques) up in Cheshire here in the UK. I say most likely because it’s currently not 100% clear who undertook the upgrades, other than it not being Caterham themselves back at the factory, but all signs point strongly in a particular direction.

I mentioned at the top that Caterham will upgrade cars on customer request, but they also enable their dealership partners to do the same to factory specification. The factory have no record of my particular car ever turning into a 420R in their care, but based on some great information from the person that sold it to me, along with information from the Caterham archivist at the factory, myself and the archivist believe that Oakmere undertook the upgrades and we’re working on getting confirmation from them that it’s the case.

Ultimately it doesn’t really matter who did the work as long as it was to factory spec. Owners of other sports cars from certain other marques might be staring at the screen incredulously at this point, unable to fathom why a lack of direct provenance about who did the work to my car isn’t a serious problem. In Caterham land it really doesn’t matter. The cars are built to be tinkered with, and it’s rare after a time to find a standard car that’s still exactly as it left the factory. There really are no two Sevens alike.

In fact, Caterham explicitly market the 360 models as having upgrade potential in the engine (look for the “Entry-level Ford Duratec with upgrade potential” text on their page about the 360), gently nudging customers towards the next level of engine performance in the 420 cars, plus the differences between a 360R and 420R motor aren’t huge. Both have the same base engine starting point and are 2.0L 4-cyl Ford Duratecs, just the 420R makes its extra ~30 bhp with uprated cams and valve springs in the valvetrain, a more free flowing exhaust, and a different engine tune as managed by the ECU. Engine lubrication is also upgraded on the 420R, with a dry sump oil system.

But that’s it, and the original buyer of my car actually specified the 420R’s dry sump oil system to be added to the 360R base spec, so it already had that. Great! That means as far as getting the car to 420R specification goes, all Oakmere had to do was upgrade the motor’s valvetrain internals to 420R spec, flash the ECU with the stock 420R tune, and fit the higher flowing bit of the exhaust system. That’s a relatively simple thing to do, so much so that I think I could do the exhaust and valvetrain bits myself (although I’d need help retiming it).

When I was researching the history of the car, which I bought as a 420R, and realised it started life as a 360R instead, initially I had thoughts of whether I was really getting what I’d paid for. But after thinking about it and consulting the oracle, I asked the right questions of the prior owner, and some of Caterham’s archivist, and got all of the information from them to be sure that it’s a 420R today.

Plus, as you can tell from the post about the initial specification which documents the state it enters my ownership, it’s been modified in several other ways and already goes past factory 420R specification in areas outside of the motor. So all that matters from my perspective is that it’s got a 420R motor, and as you’ll see in future posts that’s definitely not in question.

One thing I am quietly sad about though is that when starting life as a 360R, the very first owner specified that it be painted in Gulf livery colours, with the base baby blue colour for the body and an orange stripe running up the bonnet, plus a black roll cage. Not that I hate the Kawasaki green with orange nosecone band and orange cage, but I prefer the Gulf-like initial look the car had. Not to worry since I think I’ll also end up painting it a different colour eventually anyway.