distributor keep failing 3 in one year going on 4th

I promise you the distributor is not failing every year. You have other issues or install issues causing failure. Are you putting in new or used dizzy's? I can count on one hand how many distributors failed on my cars over the years and still have five fingers left. If they are indeed failing, you need to look at external issues that are taking them out. Bushings, advance plates, gear wear, etc .... are more likely the issues.