Gene Kearns -

A designer really has his back to the stress wall if he has to use
4340/4350 steels. It doesn't make sense to compromise the fatigue
capability for machinability in a part like this.

Don't all the Lycomings from 100 hp thru the big 540s (or even 720s?)
have the same OD on their crank and rod journals?

I still wonder about the condition of the damper system(s). I'm sure
Lycoming would have checked that out, but maybe a nasty service
bulletin or AD will be coming?

NRP