FWIW (as I am not a zetecer) I think a (the) key problem with zetec is the small valves relative to cylinder displacement. The SVTF head is new with big valves and big ports...could maybe get SVTF big valves (with upgraded springs & retainers) installed with appropriate porting.. zetec intake manifold looks bad as well, the variable runner style SVTF intake looks nice (and NOT like the duratec). cams as hot as you want next.. Now you are cooking..Well the nodular iron crank may be an issue over 8-8.5K?? rods, pistons..thats alot of cash guys..
