Razomatic

Photo 1 shows you what I started with. Photo 2 shows you the prep work removing all the surface rust. Photo 3 is the result from Jet-Hot.

I did a JetHot on my headers, collector, and muffler. I have not used it long enough to give you a perspective on longevity, but one observation is that it's a more fragile finish than I expected. Be very careful because you can scrape and scratch it if you're not careful. That might impact your color choice. Consider the higher temp coating. I hear it's more durable (and more expensive). If you're applying this coating to a used system, you'll want to spend lots of time on prepping the parts. Jet-Hot does not do that for you. If you have surface rust and want a clean finish, spend the effort to clean it up because although it covers the rust, it doesn't smooth it. The finish is thinner than I expected. I don't know if the underbonnet temps have really improved, but the finish looks very good and there is zero rust or discoloration.

Wddfour, have you tried Redline? https://redlinecomponents.co.uk Chris is an incredible resource and may know how to obtain the seats. The Caterham part number is 77624 for the seat you want. Described as “non-reclining individual seat, leather.” it was also available in Nylon under a different part number. This was an optional seat for all Caterhams until 1990. The headrest was added at some point after 1986 and has part number 77657. Headrests won’t work with the FIA rollbar of the era, if you have that fitted.

Maybe you've found your replacement seats, but FWIW my BDR has the very same seats and they are the same leather seats I've seen fitted to all 7s of the era (mine is 1986) that didn't use a bench. Mine were very worn and I purchased a better used set from another owner (1987) who was moving up to racing seats.