Bob the oil guy website guidlines

[Ant]

YOUR QUOTE:
5) 99% of the population should be using 0w20, and the other 0W30. He recommends no 20W50 etc. He said in an older engine you might want to use Mobil 1 0W40 to compensate for wear and it has higher phosphorous and zinc level than other oils. 1,000 and 1100 respectively.

No exactly BS, He did say might want to use, but a lot of engine builders who also race their product tend to stick to certain viscosities with mainly V8 engines designed in the 1960's, that of course doesnt mean you cant reduce startup wear with a 0w-40 oil and of course if that oil does the job hot and also has the right makeup of additives for flat tappet camshafts then no problem.

Castrol and several other oil companies make specific oils for old technology engines, they tend to be 20w50 or thicker, I guess this takes into account fuel polution etc contaminating and diluting the oil so in race engines start off thicker......! For road use Mobil 1 0w-40 might be great but reading the applications for the 0w grades the oil manufacturer specifies these grades for modern small engines and larger engines the heavier grades.

I am still not sure what to exactly use as this car is going to be road driven as well, and like a lot of others on this forum I would prefer to see Schaeffer make a 10w50 as I think 20w oil is too thick when cold, hence I will heat first in colder climates.