906 Head shop

http://www.musclemotorsracing.com/muscle-mike-blog/119-cnc-ported-906-heads

I would say those numbers are not typical but they are attainable.

IQ52
What was the cam profile (lift/duration) on that monster? Even if your cam was .700 lift, you are almost 2.1 HP per cfm and with an open chamber, only 6900 rpms and not even 10.1 compression that is impressive.