There's this turbo Z at the local pick and pull with a P90 head on it. They guys there want $55 for it, plus tax. My Z currently has an N47 head on it. From what I've seen, the N47 utilizes square exhaust ports, while the P90 has round exhaust ports. I was thinking about taking the P90 head, building it up on the bench, and dropping it on top of my motor when it comes time for a rebuild. My question is, does the P90 offer greater performance potential for a NA motor, or should I just stick with the N47.

thanks