[Andy Saunders]

As Bill Walker pointed out, you may be able to establish which aircraft was fitted with which engine at delivery and as marked on the AM Form 78, but subsequent changes to the engine (ie replacement engine) that had originally been installed at point of delivery to the RAF were not generally recorded on the AM 78.

So, good luck anyway....and here is one to start you off:

I can tell you that Merlin XII 11723 (A140950) was fitted to Spitfire P7386, although the AM 78 records no engine number at all!