Install the scraper.
The scraper does 2 things. It’s primary role is as a right-side oil pan baffle. The goal is to keep the oil pump pickup covered. The scraper makes it harder for the pool of oil in the front of your pan to slosh up the right side of your motor. The scraper has spring-loaded trap doors in it tho that make it easy for oil on the right side of your motor to go down thru the scraper and get to the pump. So on the right side the oil finds it hard to go up, but easy to come down.
The 2nd thing the scraper does is act as a scraper. A genuine crank scraper has fingers of sheet metal that reach up and almost touch the central axis of the crank shaft. Because of the design of our motor, our scrapers are, in contrast, well below the axis of our crank. Since it doesn’t really reach up to the central axis of the crank, it’s not as good a scraper as other engine designs allow.
Imagine the inside of the block as a crazily frenetic environment of spinning oil surrounding the crank. An oil tornado is a useful image. Oil is squirting out of the main bearings and rod bearings and being whirled around at 6k rpm. The scraper’s fingers of sheetmetal almost touching the crank’s lobes as they spin by significantly reduces the oil and air tornado because it largely blocks any 360deg path for the air/oil to whirl around. Therefore the oil that would otherwise be “attached” to the crank falls to the pan.
This increases the oil volume in the pan. And by rapidly pulling oil off of the crank, there’s also a slight increase in efficiency. Parasitic losses are reduced by minimizing the oil hurricane, even if you’re unlikely to actually notice the small hp gain. From the estimates I’ve read, I’d guesstimate 1hp.