Dirtymilkman

The 237 maxidyne when it debuted in 65 I think was argueably the biggest breakthrough in diesel engine technology at the time.It was a turbocharged " high torque rise " engine with a 5 or 6 speed triple countershaft tranny to handle the torque.I'm not an engineer,but I know how they pull! You wind the thing  to 2100, as you pull you can let it drop to 1200 before shifting. On your Cummins or Detroit of that era you have to shift at 15 or 1600,If you lugged it to 1200 it would overheat ,the Cummins often warped or cracked a head! Hence the need for a pyrometer.The first time you drive one and don't let it " drop" it won't shift without grinding,but once you get used to it you're "golden"