When having an engine machined, it’s a good idea to write down all the sizes and specifications and leave the list with your engine machinist. That way, when you specify 0.002-0.003″ end float and it comes back to you with 0.009″ end float, it’s your machinist’s problem.
A-series engine thrust bearings only come a few thicknesses, and this was well outside the range that could be fixed with standard oversize parts. Once we’d finished shouting, we found that there’s a special, massively oversized thrust bearing available, and our engine machinist was able to mill it down to the custom thickness needed.
Strangely enough, having had this near disaster, we went back to the same machinist for the head work. More on that later.