I am getting ready to change oil in my 53 with a tired 216, and I asked at the FLAPS about 30W. It doesn't seem to belong to the standard assortment in Sweden, but they did have 50W. I bought 4 liters, but have not changed yet.
So the question - is it a bad idea to run straight 50W? I figure my alternative is to mix it 50/50 with regular 10/40.
Karl

It may not be the easy way, but it is the Cowboy Way - Ranger Doug
Beware of the stories you read or tell; subtly, at night, beneath the waters of consciousness, they are altering your world. - Ben Okri
1953 Chevy 3100
1960 Volvo PV 544
1941 Chevrolet Special Deluxe