Wilf that is what I run in my motor. The bearing clearances dictate I use an
oil in this weight range. I too change the
oil every 2000 miles and it comes out looking good. By all indications, this a a good choice for my motor. My builder, an FE guy for many years recommends this
oil for all his motors.
There is a lot of good reading on the Web regarding the composition of various oils--ash, other compounds, etc.