40mm is certainly more spacer than I'd ever use. If the steerer is metal, then you're OK, but 40mm is a lot for a carbon steering tube. My LOOK frames came with 30mm, so I assumed it was the suggested max.

If you flip a -8 stem, it will raise the bars by at least 25mm, but the horizontal stem length will also decrease by 8mm, or nearly one stem size. but removing 25mm of spacers would restore the horizontal position of the bars.