Ay up Stempy, This may be of use to you... http://www.z1enterprises.com/Z1CarbGuide.aspx Scroll down to bottom of page. I've got 720 big bore kit in my 650, 29mm Smoothbores, K&N, Pingel hi flo, Harris 4-1 and just been to Projex in Cradley for a Dyno and setup. Ended up with 25's and 120's. Run...