The Indy valley traps a lot of oil that remains after shutdown but yes you are correct that the lifters in the first few seconds of startup get very little if they were not drilled for it. Regular lifters can handle this without much trouble but YES I suggest a preoiler on any serious motor. It is just cheap insurance on high dollar pieces. We used to block ALL the oil off to the left side lifter galley and those motors ran fine. Not much anymore as most guys wanting that type of deal just buy a race block. Todd