Shortened McCauley Propeller on an O-300

A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he had
bought for his Emeraude.

Now here's an aluminum McCauley which was originally 76" and is now 75.188.
In other words 13/32" have been removed from each blade, reducing its
diameter by 13/16".

It seems ac 43.13A, McCauley, or the tcds ought to say something about this
and the limits a prop may be shortened but I haven't found it yet. Anybody
know if this prop would be legal on a certified aircraft with a Continental
O-300? Or can direct us to the pertinent specs?
Thanks.