Cast Iron Chucks

[Morrisman]

Nearly always cast steel, not cast iron.
Of course, you still get cast iron rods, which is also why sometimes they break and put holes in blocks after someone has been tinkering with them...

Sorry, but there are millions of cast iron crankshafts out there and it was the norm for decades. Maybe modern cars use steel, or hi po race motors, but cast iron cranks have been successfully tuned and raced for generations. I’ve used them in small block Chevy motors that rev to 8000 (occasionally accidentally) rpm and put out 500hp.

 

[Morrisman]

Correct Dan, the old Norton Commando's had cast iron flywheels and they were known to detonate if the revs climbed too high. I believe it was an experience once undergone, you'd never want to repeat.

I had a couple of friends who used to ride Norton’s back in the day. One was hogged out to 960cc with something like Lotus Cortina pistons in. They were for street use only but were pretty damn quick. He tried a belt drive conversion on that one but it would not last, just tore up from the torque.