BILL "QQ" J. - about 96-97% of IH's cast iron was gray iron, their foundry in Waukesha, WI poured some ductile, also known as nodular iron, pretty sure that was their only ductile foundry.
Had a nice l-o-n-g conversation years ago with a couple metlurgical engineers who worked for a company called "Metal Improvement Co",
http://www.metalimprovement.com/ Yes, both gray & ductile iron could be helped a LOT by peening. At the time SON had just had a conn rod failure on one of his R/C engines, which was machined alum bar stock with pressed in 660 free machining brass bushings. The R/C "Boat Racers" who used the same size engines as our truck & buggy engines used to have rod failure EVERY run, well, maybe only 75-80% of the time. The company actually "peened" those conn rods. It didn't improve fatigue strength enough to run a rod twice, but at least they could make a full pass under power. Our little 1/8th cubic inch engines made around 1/2 to 5/8 HP @ 30,000-32,000 RPM. The boat engines were making around 1 full HP @ 40,000+ RPM.
KEITH O. - Yes, IH could have ground more casting parting line and casting flash, even improved their painting quality... and raised the already high price 25% for no real added value to the customer.
KRAIG - I only went to Travis's PD's twice. Took Ken U along both times, followed Wyatt the first time from Monona, Iowa to Travis'. Second time Hank Will went from WAY out at Gettysburg, PA, and pulled into the field just five seconds before we did. Since I always plow w/72 and my same plow, can't really say if the pic' you posted was from my 1st or 2nd Iowa PD.