From experience, fuck that! I got my piper 285's for free, and fitting them cost over £300 in machine work. The buckets come in varying sizes for the st170 engine, each bucket costs £16 trade price from ford, so 16x£16! Or. You run valve top shims, but again, still costs loads to do. I would buy another head in better condition. The power increase the cams gave me was fuck all. I wasn't running the vvt, had the inlet cam modified to take a standard vernier pulley too. I was running ITB's