My kit has been supplied with version 1.2 of the IKEA style manual. This manual really only covers the 270 / 310 models with a few references to 360 and 420 models, but doesn’t cover anywhere near enough detail to build a 420. That means I am left to download the old-style 2015c manual from http://caterhamcars.com. I actually prefer the old manual, even though it has been complained about in blog and forum posts for a long time.
I used the old-style manual when I built my 360R, so I am used to it, but using both introduces an interesting conundrum. What to do, when the old manual contradicts the new manual? I suppose this is nothing new, because the old manual used to contradict itself at times. The main area where this seems to happen is torque settings. If I see any obvious examples I will put them into the appropriate post.
UPDATE – A new Duratec version of the manual (v2.0) has been created. A New Duratec Build Manual
caterham420detailedbuildblog.co.uk 
I suffered the same conundrum (on a 420R). For good measure there’s a third list of inconsistent torque values in the owner’s handbook. I generally went with the higher torque setting unless it felt excessive. Inadequate torque can result in bolts failing due to fatigue…
Nothing in the build manuals on the dry sump system either…
I passed the IVA on 27 December 2019 and I’m waiting for the registration.
Good luck!
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Congratulations on the IVA Simon. It’s a shame the 360 / 420 manual is in its current state, I assume Caterham has concentrated on the models they sell the most in kit form.
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