Interesting link

It covers ZDDP versions for all kind of oils, not only motor oils.
I copied the part below of a comment that also mentions the viscosity as a vital part.
(The context is drag racing engines where they use thin oils to get more power
Moly on the other hand can be bad for the wet clutch. I have read somewhere that there are different types. Not all bad for clutch.)
"If your priority is wear (especially cam & tappet wear) then your priority should be to use a heavy oil containing not a lot of shearable VII; something like a 'tight' 20W50 for example.
I used to get paid to sell additives and yes there's a lot you can do to counter wear with Zinc & Moly.
However, any formulator worth his salt will tell you that, in terms of anti-wear, there's no substitute for non-shearable high viscosity & the presence of some genuinely heavy base oil in the blend.
By all means slap in a goodly amount of Zn & Mo on top but go heavy! BTW, it won't matter what type of ZDDP you use at these kinds of temps as both will be well above their respective activation temperatures."
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I have found interesting info on Porsche forums. The older models are aircooled and even the later (1980's) are specified to use 20W-50 as CB750.
https://rennlist.com/forums/928-forum/709018-oil-and-zinc-additive.htmlPost #6 has nice info.
+ From post #37
A long interesting post where the oil's film strenght is mentioned as a top priority.
(I have read this on other forums too. That's why I believe in V-Twin oils where the oil film has to work with a much longer stroke than a CB )
.....
Zinc is used as an extreme pressure, anti-wear additive. But, zinc “DOES NOT” build-up over time like some type of plating process. For those who have actually taken an engine apart that has been running high zinc oil, you know that you don’t find a build-up of zinc that looks like some sort of coating or sludge build-up. Zinc does NOT work that way. And zinc is not even a lubricant until heat and load are applied.
Zinc is only used when there is actual metal to metal contact in the engine. At that point zinc must react with the heat and load to create the sacrificial film that allows it to protect flat-tappet camshafts and other highly loaded engine parts.
Another thread:
Post #9 below
https://rennlist.com/forums/928-forum/1335715-bruce-and-sean-buchanan-buchanan-automotive-on-oil-tt-and-tbf.htmlPost #16 below
https://rennlist.com/forums/944-turbo-and-turbo-s-forum/973124-oil-question-for-my-951-a-2.htmlPost#5 below
https://rennlist.com/forums/968-forum/854352-968-engine-motor-oil.htmlI have read another thread where the guy Buchanan/Jet951 had commented the viscocity importance and also found how quick it could degrade.
Castrol oil tested after not long use. Also how Porsche engines failed quickly due to low viscocity oils.
The Porsche engines are used as street cars plus track days.
Like a modified CB750 with occasional speeding rides.

So, what have I learned now?

,;D
- Viscosity (not too low)
- Film strenght (V-Twin oils must have that)
- ZDDP that last. I'll follow the Spectro mineral example of 1900ppm level, Redline ester synth only 100ppm more.
