they have the right position in gmax and you used taina's replacer-tool to convert the files for the game, I assume?
well, head-models are a damn tricky thing. taina's replacer can only handel simple vertex-movements, but no movements of helpers and such things (dunno about animations).
to get such stuff changed, you have to use mdlops to recompile the mdl and mdx files. but if you do that with a head-model, it'll float on the shoulder rather than be attached to the neck.
the only way to get that fixed, is a naaaaasty hex-edit guessing-game which only a few modders ever managed to do a handful of times, afaik.