A good question for a metallurgical engineer. I am sure it would help a lot if you knew the alloy composition of the block and crank. A metallurgical engineer could prepare a small speciman of each and tell you their current state of composition based on microscopic analysis of their carbon content and the Iron Carbon Equilibrium Diagram of heat treating. Time, temperature and transformation during heat treating are super critical. Here's a good article.
http://www.epi-eng.com/piston_engine...ign_issues.htm
Here's another;
https://www.ductile.org/didata/Secti....htm#Annealing