I would ditch the piper straight away id your chasing those sort of figure only for the rishk of it chewing itself, spewing swarf into the block and taking the engine with it.

Speak to Norris motorsport, I had an interesting chat with them yesterday regarding cylinder heads and they were very helpful, I also found they have their cams custom ground to their own specification by Newmans who are the market leaders in producing cams from the best blank material (something which kent./piper have yet to achieve IMO)

Other people to shout to is Christian@APT, Simon & sitech and Jamie@jamsport, these guys are all running well over ther 300 mark so you know their advice will be as it is not forum talk.

Hope this helps mate

p.s. what is the rest of the spec as the figures you are chasing are serious ones especially for that lickle 1600.