SUPPOSED TO, USED TO, HAVE (HAS) TOI checked three learners' dictionaries: Longman Advanced American, Oxford Advanced Learner's, and Macmillan English. None notes the voiceless version of "supposed." All three give "used to" as a headword and note the unvoiced "d." Longman and Oxford note the voiceless version of "have"; Macmillan omits it.
Note that these three phrases have different meaning depending on whether the relevant consonant is pronounced voiced or unvoiced. "I am /suppozd/ to be in charge" means that people suppose that I am in charge, while "I am /suppost/ to be in charge" means something different: that I should be in charge.
Toothpicks /yoost/ to be /yoozd/ for picking teeth, but nowadays they are /yoozd/ more often for building miniature models.
"What do you /haf/ to do?" means something different from "What do you /hav/ to do?"
In the third-person singular form, "whatever he /has/ to do" means something different from "whatever he /haz/ to do".
The dictionaries I have looked at note the differences in meanings, but not the corresponding differences in pronunciation.
(July 13, 2003)