If the word ends in silent e, drop the e and add the suffix, unless the final e is needed to preserve the sound of the preceding consonant.
Which spelling word requires the final e to preserve the sound of the consonant before it?
I would say that the spelling word that requires the final e to preserve the sound of the consonant before it is vengeance. Because if you omitted the final e, it would be - vengance, and that word would be read differently. This is why the final e needs to be kept when adding suffixes.
