Jacobs was good stuff. Dr. Jacobs actually invented the multi-spark discharge but I believe he sold the rights to Autotronics (MSD). I still have a Jacobs pro-street box laying around. years back I talked many times to the Jacobs tech's and they told me the multi-spark capacity discharge was designed to fix GM HEI issues. the last I heard on MSD boxes is they have a 25% return rate due to problems.