It's always worth asking at a decent dealer, you might find an enthusiast who is willing to help.
The Ecotec engine in my 4/4 is a GM/Vauxhall/Opel unit, and when I went in to my local Vauxhall main dealer to order timing belt and cam wheels for it they were fascinated that I had a Z18XER engine in a Morgan. A couple of them trooped out to have a look at it, pointed out the non-standard components (of which there are hardly any) which was very helpful and then made me an honorary member of the Sri Owner's Club so they could give me a 10% discount. Good lads.
