I have had a look at this for my Streetglide 107 as my bike was manufactured 12/18 it has the old oil pump fitted ,Harley Davidson upgraded the oil pump on the late 2019 upto current models so from what i read is that if you fit this modification to a late 2019 or later model it will be fine but for the earlier models like mine it will puke oil out of breather mod , The upgraded oil pump in the later models is fitted with an oil seal against the crank bearing side and also modified 8 lobes on the return side of pump as compared with 10 lobes on previous models , So i have decided the best option for me is to fit a new camchest with high volume oil pump to fix the sumping problem with my model which pisses me off because i have already had a stage 2 fitted and if i had known this at the time i would have fitted it all at once 

hi guys I think people check their oil levels differently this is apparently the correct way, some people seem to over fill their bikes-  https://www.youtube.com/watch?v=thzjNfl95ro It's surprising the Screaming/Eagle stuff is cheaper than S&S or Fueling? from what I've heard the S/E stuff is pretty average especially their lifters & oil pump 

The issue is the oil pump on the early models. Putting less oil in than recommended is just a backyarders way of fixing the problem.