I was pretty sure the LS pump was in the front of the engine, and assumed the front of the engine would get
oil first. Wrong! A quick internet search showed that the pump is indeed in the front of the engine, but the front mains are the last thing to get oiled. They route the
oil to the back of the engine, through the filter, and then up to the cam bearings. The
oil then works its way to the mains, one at a time, until it gets to the front of the engine.
What a crappy oil design! You may want to do some searches for oiling improvements for that engine. It is a very popular engine. I have to believe that someone racing this engine has came up with some oil routing improvements.