I have struggled with the cabin heater all weekend. I could not get it to sit correctly on the muffler, it made no sense to me. After thinking about it for hours and trying to find what I had done wrong, I came to a decision. The shroud was too wide, so I trimmed 10mm off one side and re-drilled the holes. I spoke to Errol today, ( Monday ) who is the Australian Sling agent, and he informed me that the 912 and 914 engine mufflers are different.( 912 wider than the 914 ) I was supplied with a 912 shround for a 914 engine, no wonder it did not fit. Anyway, I think it fits OK now, it has taken me most of the weekend to sort it out. It was a frustrating weekend in the build shed for such a straight forward job.