I eventually decided to do away with the IMRC altogether, and just jammed the secondaries open with a twig and a tie-wrap in the mechanism on the end. However, before doing that I was researching the IMRC for a certain V6 Mazda which looks pretty much identical. All the photos I've seen of it have it branded as "Ford". If I wasn't so happy with having no IMRC, I'd probably have taken a punt on the "Mazda" part which is substantially cheaper.
Am just mentioning it in case you want to research it yourself:
Hi, I know this is an old thread but just wondered if there are any drawbacks when you jam the secondaries open, also is it a difficult job and how do you do it? Many thanks!!!
The general consensus is it actually works fine with them jammed open.