In an attempt to condense some more info that has been seen before, into one fresh thread, here is my modest contribution.
As always, click on the images for a larger view.

This, clearly, is an original AY engine. With reference to the large distributor, it will be noted that it serves eight plugs, so these engines used two plugs per cylinder.
The original design & prototype head [& engine] used only one plug per cylinder but production[?] heads used two.



















This well known & over used image shows an AY in a rear drive car. Note that it is using a 'standard' competition oil pump. I suspect that the pump in the previous illustration uses a special cover on the comp. pump to allow use in a front drive car.
















As can be seen from this image, the studs that secure the rocker cover, also secure the rocker pedestals.
There are four unidentified objects along the aproximate centerline of this head & I speculate that these are the four additional spark plugs that these engines used.
The new production heads that are being developed will revert to the original single plug design.


























As for the AZ engine, I suspect that it never got beyond the design proposal stage as we have never seen reference to it anywhere else but it would be wonderful if one or more were actually made.
I wonder of they used a short cam section in the block to drive the oil pump & distributor, & I wonder what the drive to the overhead cams looked like.

EDIT
The AZ also seems to be a 'dry sump' design so I wonder how the scavenge pump was to be driven & what is the object depicted in the position where the distributor would normally go.