Time lead sled time. How long was your over speed. ???????
yr right,
About five seconds, less than ten seconds, as short as the standard procedure for the failure could reduce the RPM.
The IO-540 is a solid old girl, just look at the RPM/BMEP used on the TSIO versions. The biggest danger in an overspeed is damage to the harmonic balance weights, if they are OK, the likelihood of engine damage is limited, if there is any suggestion of balance weight problems, it is a bulk strip. (The overspeed was as near a makes no difference, 10%)
You should read what Creampuff has to say, and consider it very carefully. What he (and Jaba) is saying is good common sense.
Having "opinions" that are directly contrary to the well established and unchallenged (by knowledgeable persons) facts is not helpful in Aviation.
Tootle pip!!
PS: The ATSB accident report on the Whyalla loss of the Chieftain was one of ATSB's less credible efforts.