Getting the valve geometry correct...

Rocker blocks too high for correct geometry, as such embarked on some milling following buying a basic slide for the lathe.

First step machining some bolts to mount the slide:

Then set the slide and trued it to bed.

Blocks then mounted in pairs within the vice to ensure matched sets, and took gradual horizontal cuts with the mill bit. 

Third block simply to match height to other pair. 

Worked well with some hand finishing needed:

Blocks in situ during measurement, adjustable pushrod in place. 

Next job: cutting pushrods to length!