Originally posted by horseydug:
Head gasket surface flatness spec from '97 service manual states the following for both block and head:

.025/25 x 25.050/150 x 150

Perhaps another member can translate.

Flatness 0.025mm per 25x25mm region
Flatness 0.050mm per 150x150 region
Addionally, the total flatness error is 0.080mm. That's across the entire head surface.