G'day vint_mow,
As far as fuels go, I much prefer no-ethanol 95 Premium. It has a much longer storage life than 91, and much less gumming tendency.
An SAE40 oil of today is very different from those of the 1960's, in terms of additives like detergents and anti-wear compounds. But a monograde SAE40 oil still meets the same viscosity standards as it did then!
You can get away with say a straight mineral 20W-50 multigrade, but it may burn a little bit, if the engine sees regular use. Synthetic and semi-synth blends are a complete waste of money here.
Penrite market some multigrade oils for classic car and motorcycle engines which are entirely suitable, e.g. their 'HPR40' which is 25W-70 viscosity, and readily obtainable.
Additives - <sigh>. Some of them can have advantages in specific applications, like gear drives in particular. Engines - not so much, as a rule. Their actual effects need to be monitored by an oil analysis program - which is worthwhile in heavy industry, when you're talking hundreds or thousands of litres for an oil change.
But the majority of them, are as you say, in the 'snake oil' class.
