Jeff:
As you may have noticed, the Zetec option sees little exposure in UK events. The K series and Vaux 16 valve units are far more common. James Whiting, and Raceline are two major parts/info suppliers. Check back through past threads for Zetec topics. Most will be heated debates over the merits of various engines, but there is good info too. In the U.S. the Z is really the best choice of modern engines, and upgrades from cross flow to Z are easy, if expensive. Best of luck.
Cheers!
Michael
X-flow equipt Yankee