I checked the block, and it looks like they could go either way... the GM book didn't specify one way or the other...
I ended up putting mine in with the oil holes pointing towards the rear of the motor. I figured since the oil pressure comes from the rear of the motor that they would recieve better pressure that way... Was I wrong? Or does it even matter at all? My guess is it doesn't matter, and I am just being over-**** again with this expensive peice of iron...

 

Doesn't matter.

 

If you notice there is a mchined recess around the lifter where your hole is, so it gets fed oil no matter which direction it comes from