I make my own crank scrapers and install them between the block and windage trays with .030 to .060 clearances on the passenger side of the blocks , I have heard from a very good engine builder in SO CA that the crankshaft scrapers they used on BB Chevy were worth no HP or torque improvement below 6000 RPM at WOT dyno testing, they made 30 HP gain at 8600 RPM on the same motor with almost identical weather conditions the next day after installing it
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
, I have heard from a very good engine builder in SO CA that the crankshaft scrapers they used on BB Chevy were worth no HP or torque improvement below 6000 RPM at WOT dyno testing, they made 30 HP gain at 8600 RPM on the same motor with almost identical weather conditions the next day after installing it 
