You're asking the wrong type of question with this engine chum
And btw, what oil should I use?
OK, this is the case:
I'm in the middle of changing my timing belt, and I discovered that the previous owner has fitted Champion RC6YCC as the main plug. This is not a platinum type, but a standard spark plug where you can adjust the gap. The correct thing would be to get new plugs of the correct type, and I will do that, but for now I just wan't to put the engine together as quickly as possible, and I don't have the time to get new plugs right now.
So as Sensingsys says the workshop manual states 0.6-0.7mm, however on the inside of the bonnet there's a sticker that says that this car uses platinum plugs and the gap should not be adjusted, just as aamrit and David C says.
After som consideration I will do like this:
I will adjust the gap on the Champions to a little less than 0.9mm, say 0.8. The car has been running fine, but 0.9 seems like a very large gap for a standard plug.
The side plug is the correct NGK PMR7A platinum type, so I will leave that one as it is.
I will also order new plugs, either platnium type as recommended by Alfa or iridium, which I have very good experience from in other engines.
After some more lurking on plugs i realize that the Champ RC6YCC fitted has wrong heat rating. Rating nr 6 on Champion corresponds to NGK nr 8, and vice versa NGK rating 6 as stated by Alfa corresponds to Champion 9 or 10.