Out with the old hot rod in with a new one

How did he use cast iron exhaust manifolds with a 440? I thought that was a no-go? And power steering?

I've wanted to build the '73 Duster I have with a 400 like Mopar would have if they had offered a 400 in a Duster of that year. But I've heard that the B motor is just ok with cast iron manifolds and a 440 was impossible.