Crane Rocker arm clearance on Iron heads issue

Not surprised that you are getting interference. The pedestal is a casting that is not machined to size & can vary in size. It is like core shift. The problem is obvious in post #7 with your caliper measurements.

You need to grind the pedestal for clearance. Do not grind the rocker, that area of the rocker has the most load on it & grinding it will just weaken it for the big bang....