MAINLY OIL WEIGHTS ARE DEPENDANT ON HOW MUCH BEARING CLEARANCE U HAVE IN RODS AND MAINS...IF IT IS A STOCK REBUILD WITH STOCK CLEARANCES,USE STOCK RECOMMENDED WEIGHT OIL.IF IT IS A LOOSE MOTOR SET UP FOR RACING USE THICKER OIL LIKE 20/50
BRAD PENN IS KNOWN FOR ITS SLIPPERYNESS WHEN CONTAMINATED WITH GASOLINE(GREAT NEWS FOR NITROUS USERS)