389

Purchased a 1966 Bonneville with a 389. On the top of the engine next to the distributor on the passenger side there is an open hole. I have no idea what goes there and was hoping someone could inform me what should be there. Any help would be greatly appreciated!

I am looking for a valve retainer for my 1964 Starchief 389. Anyone know where I can find one. I have called Ames and they do not have any. The OD is 1.3225" and it is for dual springs with a 7 degree for the keepers I believe.