As to mic-ing and gauging the assembly as you go, OH YES! There is quite a bit of checking for clearances. For example, each push rod was suspended in a jig and I rotated them all under a feeler to check for out of round. According to Kelly, Lycoming allows 7 units (degrees? mm? parsecs?) out of round, but ASP wants 5 or less. There is lots of that.
Though I had a great time in the Build School and recommend it highly, if you can't do it, you can rest assured that your engine is being built right by these people.
Clay "Cookiemonster" Cook
USAF: T-38, F-111F
American Airlines: 727, MD80, 757, 767, 737
RV8 #81751 project sold
RV8 #81651 project acquired
Donations up to date thru December 2015