Just for information, here is the lifter valley of the R3. Pretty different than the stock block in terms of 'topography'.
Also, the .046" holes in the lifter bores. These are sitting in a .125" recess that is .125" deep....I did that to reduce the depth of iron I had to drill the .046" holes through
View attachment 1715563444 View attachment 1715563445 , and to provide a small, wider pocket for the lifter hole to match up with.