I have decided to replace the two ball studs that were collapsed (until I removed them) as well as one other one that seems particularly "soft". After completing other items on the list of things to do before reinstalling the engine I will get the car running and sorted a bit before doing a complete checking of the ball stud/ rocker arm/thrust pieces.
While chasing the clicking sound I was hearing from the left cam I found that the cam sprocket was loose and had hammered the Woodruf key enough to allow 3-4 degrees of play. This is just a normal key and not one of the ones used to adjust cam timing. I was only able to find the offset keys while online shopping.
I have read a lot on this forum concerning the aging and break down of the material used to make the chain guides and the importance of changing them as they age. I haven't however seen anyone talking about (nor do the achieves contain) any experiences with slide rail failure. The guides on my car look new but the slide rails behind the timing case cover are very dark brown. Obviously these are no picnic to change out because the necessity of removing that timing case cover (and everthing in front of it) complicates things. But if the guides are prone to failure than I would assume that the slide rails are too. Has anyone had any expience with slide rail failure or replacement?? Do I have more important things to worry about than the slide rails??