That may be enough to cause a leak.
I can't comment on the Ford Specifications but when I used to "turn a wrench" for a living in the early-to-mid 1980's, the rule of thumb for overhead cam cylinder heads is "If they are warped more than two-thousandths of an inch, they must be replaced". The reason they must be replaced is the camshaft bore is also warped which could cause it to seize-up leading to catastrophic engine failure.
Since you didn't specify that this is actually a Contour, if the car is not an overhead cam engine, then you should be able to get the heads resurfaced to cure the warpage.
Dave Keller
1995 Contour SE
1999 Contour SVT
