I have read several posts about this and all seem to have different advice so I apologize about bringing this up again. I have a 340 with edelbrock heads and what I believe to be 273 adjustable rockers with the banana groove shafts. I have always heard to orientate the groove on the shaft to your left side notch facing down. Then I read that this may not be correct and some shafts were not assembled that way. When I place the shaft with the groove on the left side notch down my oiling holes face towards the engine and I have read that they should face towards the valve spring. Also I have read that the banana grooves should face up and then in another article they should face down. I am so confused.