.557" purple shaft 318?

Everyone's definition of streetable is unique. My impression is if they are running that hard they are not what I'd consider streetable. In the US we build bigger engines. They are the same money and we can get more power from them.
Do you really think the cam is what makes them run that well? And no, it's not like Zepplin. Zepplin's art, which is timeless. Purpleshafts are technological, and as such are way behind the times. Yes, they work, but there's much better around now.