are these sentences correct

[scott833]

1) The manager turn out to be different than my preconceived notion.
2) He look different than my preconceived notion about how he looks like.
3) He turn out to be different than what i thought.

[chadley25]

All of these sentences need to be in past tense. There are also a few other minor issues.

1) The manager turned out to be different than my preconceived notions of him.
2) He looked different than my preconceived notion of how he would look.
3) He turned out to be different than what I expected.

In each of these, you may also use different from rather than different than, especially in spoken English.