Ron,

 

I installed a JPI EDM900.  It came with a mag sensor for the tach.  It looked a lot like the one that came on my factory reman IO550N.  I talked to JPI and they told me to just cut off the round black connector and don't bother removing the mag to install the sensor that came with my JPI unit.  I installed a 3 pin molex and never touched the mag.

 

Mike