BTOG has a lot of information and like a lot of us is on a quest for the best
oil for our applications.
These statements like 0-40 for our engines is just BS.
Use the
oil that has is built for eg flat tappet camshafts normally a race
oil that can be used on the street etc etc.
My Toyota Vitz 1000cc they recommend 5w30 so I use Castrol Edge 5w30 full
synthetic as I travel 100 miles round trip to work.
I am going to use Schaeffer 20-50 race oil in my Cobra and it will be heated in the oil tank before use. I use what my engine builder recommends and what the leading race guys are using plus Schaeffer oil is recommended for extended oil changes. Schaeffer oil has excellent start up properties, the only minor detail might be a slight hp loss due to being thicker, I would prefer to have the protection when hot and under hard use. For the road I would use Chevron 400 15w40 as I know people that have done 300,000miles in petrol engines still going strong this oil is made for diesel and petrol engines.