Is anyone aware of an oil leak problem that is being reported frequently on both the 4.6 and 5.4 blocks? Apparently there was a problem during '98 &'99 in the way some of the decks were milled. The heads don't seat perfectly and oil leaks occur at the rear where the oil gallery runs up to the head.
Replacing the head gasket apparently doesn't seem to work, and replacing or re-milling the the block is the only correct fix. I'm told the problem was fixed in '99. There is no TSB out on this but Ford apparently is quite aware of the problem. Consequently this has created a shortage of blocks for warranty work.