They'll take more. Chrysler never used "just" cast iron like Chevy. They used nodular iron, which is a good bit stronger. I always give Ford's 351 Cleveland as an example. They never came with a steel crank, but nodular iron. These engines routinely saw 9500 RPM on the NASCAR circuit using the nodular iron crank. Nodular iron cranks can live quite well with good prep work and parts.
