Here's the contents of Ed's email with his comments.
Brian
8227

I ran across the LMC UK thread about ”matching numbers” for a Fulvia 1600HF, and you’re absolutely right; the only possible “matching” numbers would be having the engine serial number match the car’s original European registration documents, from a country that noted both engine number as well as chassis number on the reg docs. Given the absence of any factory records, that’s the only possible documentation that could establish what engine that chassis was born with. And that’s the only thing “matching numbers” can possibly mean for a 1600HF; the 1600HF is one model that absolutely cannot have its engine serial number numerically match its chassis number. The chassis numbering started 818.740/1.001001, but the 1.6 engines never changed designation; they started 818.540.1001, with the S1 1.6HF (and works rally cars) taking at least the first 1500 818.540 engine numbers. And, of course, the numbers didn’t even numerically match on the S1 1.6HF; my chassis 871 has its original engine, 804.