(1) It would have never worked.
(2) It would never have worked.
(3) It never would have worked.
The adverb 'never' is a frequency adverb and as such needs to be in mid-position. Mid-position adverbs are usually placed between the last auxiliary verb and the main verb. 'would have never worked'.
Some speakers move it around in this general area as your 3 examples have done. When you do that it's necessary to put a bit of stress on 'never' to signal that you want it to stand out. never would have worked/ or would never have worked.
On a side note, we don't usually put frequency adverbs at the beginning, (initial position) or at the end, (final position) of a sentence.
In English, if you place a word where it normally doesn't go, you have to put stress on it to show what you are emphasising.