273 banana groove rocker shafts

The shafts you have are the stock 273 shafts. You have two oiling holes, one in the banana groove to spread the oil on the load surface and a second oil hole for the adjuster and pushrods.

The grooves face down at about the 6:30 position or slightly towards the valve springs and the second hole is towards the inside of the engine.

As mentioned above in a previous reply above if you install the small notch in the end of the shaft facing down to the front on the drivers side and towards the back on the passenger side. This is the orientation outlined in the factory service manual. When installed this way you will end up with the banana grooves facing down for the load and the second oil hole for the pushrod towards the pushrods.