The book of words says to use 5 star petrol... 5 star was 101 octane. So running on factory settings with petrol that you can get these days, pinking is only to be expected.
Plugs aren't going to be making it worse if the existing ones are a healthy colour. Carbon deposits or that ceramicky stuff you get with them might, if the engine hasn't been taken apart and decoked for a long time.
I've just been accepting that the factory settings aren't directly usable with available petrol, and just using them as a starting point. Set it by the book, then go out to a suitable test hill with a spanner in my pocket and if it pinks, pop the bonnet and tap it back a fraction. If it doesn't pink, tap it forward until it just starts and then back it off until it stops.
This is no big deal, since the factory figures for any car are a one-size-fits-all compromise and this method gives a setting which is more accurate for the specific engine in question, so I'd be doing it just the same on any car. It just means that on a 164 the final setting ends up a wee bit more retarded than the book says, whereas on something like a Morris Minor which doesn't want high octane fuel anyway it may even end up a bit more advanced.
Quite why the B30 wants 5 star when the B20 which has the same combustion chamber only wants 4 star is not entirely clear, but for carburetted engines at least, my guess would be that the heat-exchanger manifold is producing higher charge temperatures, even when the bypass valves are open.
As far as the injected variants are concerned, I found that a B20E was actually improved by using the thicker B20A head gasket and thereby dropping the compression slightly. The expected loss of a few hp at the top end was not in practice noticeable, but there was a noticeable increase in flexibility in the mid range which made it a better drive. That was before unleaded, using real 4 star, so pinking didn't come into it, but I would expect the basic point to apply just as well to the B30E, that dropping the compression is not something to be afraid of.
Since it is possible to buy TEL as an additive, the pukka solution would be to use that and give the engine the fuel it's actually intended to have. It's not something I'd be keen on doing, though, because not only is the stuff foully poisonous - organic lead compounds are much nastier than the elemental or inorganic compound forms which are what you normally encounter - it is also absorbed directly through the skin. TEL massively diluted in petrol is one thing, but neat TEL is a bit different and not something I'd want to fiddle about with in petrol stations. Or even in a lab, really.
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