dirt track SB, oil/filter changed after each race. what micron filters should I use for breakin & thereafter? I have some 20-50 oil that I can use for breakin or I can go thinner on this if you think it is too thick. & any recommended brand of filter? thank you for your time.
Spend on some time on the K&P Engineering website and you'll learn some interesting stuff about filter ratings. Basically you can't always believe what is written on the box.
https://kandpengineering.com/technical-information/ 
