The orange head (z852) is a damn good truggy mill.7 port with mid range port timing. They do make a 7 port with a high rpm powerband, which is the green head (z862), you can pick them up for around $220 or so.

There is a guy on rctech (22 racer) who does engine modding, his company is TQ mode. He's a alpha dealer, and his son won the J Concepts nationals on Omaha with a stock green head alpha by over a lap.

Pm me and I can give u his contact info.