Have been chatting on another forum and a guy that's sort-of involved in aviation says he has a friend who worked for Boeing
My sisters boyfriend's best friend told me that... Aircraft are not bridges. 75 mm does not in any way surprise me as 3 inches overthe 231 feet and 10 inches the 744 shoots for.
Thermal expansion is a factor as the production length is at 70 deg f, the length that the person who told he person who told you could vary that much depending on the temperature it was above or below 70 deg when said aircraft was measured.
Not for nothing but the guys who are putting these aircraft together are not the finest of scholars, most of them have one little section of the aircraft that they hammer the same rivits into day in day out.
From personal experience with thermal expansion, I have done my fair share of rigging and building aircraft cables. Fact is they are often a bear to deal with on long runs as the aluminum contracts/expands at a different rate than the steel cables do. There are calculations for tension based on temperature and the job is allmost impossible to get done right unless the aircraft is at a controlled temperature for a decent length of time.
3 inches could easily be made up for over several turnbuckle connections, it happens on ocassion that cables have to be custom made.
Bottom line yes an aircraft could be 75 inches off spec and no the manufacturer and operator probably do not give a damb.