JD Hord has a wealth of knowledge on the twins, he has made a career out of them.To the OP: sorry also for going off topic. I have heads ported by JD Hord but as they came in a motor with Wiseco pistons and some other mods I can't give a back-to-back comparison. Yet to dyno the bike but will do so after NY. I left the porting entirely to JD, he ports the heads depending on what cams are being used - Mori Stage 1's in my case. If you'd like to know just what gains can be had with head porting alone then ask him, I'm sure has checked it out.