a p8r head has the same combutsion chamber as the pr4 or p75. the only advantage is the bigger valves and more duration on the cams.
it builds monster torque and can flow really well.

guys on boost should be chasin this head.

as far as the head its self, it came on the b20z (only about 5% of the total engines were these) so they are a bitharder to find. verry similar castings to the pr4 and p75, just bigger valves and cams for torque.