Charles, Dave is correct. If your most recent common ancestor is more than four or five generations back, you may not be able to use autosomal DNA (Ancestry, 23andMe, or Family Finder) to determine if you're related. If the person you're trying to match is also a man with the surname West, your best option would be a yDNA 37 marker test from Family Tree DNA, assuming that he has also taken a yDNA test. That test can go back many more generations.