[Bruce Lancaster]

The KRW lifteruppers were just for locating valve train noise and misbehaviors.
They were NOT intended for adjustment because no Fords had any provision for any sort of adjustment that could be done on an assembled engine.
The intent was that the mushroom stem valves were set by length* at factory assembly assembly and reset only as part of teardown and valve job in service. The idea, supported by mushroom stems and later by hardened seats, was that the valves would not need adjustment until the engine needed major work anyway. I do believe it worked...flathead valves in normal service don't need adjustment in use. Obviously the factory numbers were based on engineering calculations and measurements of what would be right hot.

*(I think the factory procedure was that the seat-to-lifter depth of a finished block was measured with special micrometer and the dimension scribbled on the block surface. Then pre-measured valve assemblies were dropped in to suit. This is essentially what would have been done in a professional garage valve job, too, measure the depth with special cone-seated micrometer, grind stems in the refacing machine. Welding or brazing lifter and cutting its top in same machine for loose assemblies, or hot rod cams.)