The 'white box' is the ballast resistor that is supposed to allow 12 v to the starter, then drop voltasge to about 9 for running, thus saving your points from burning up early. With an electronic ignition, you did the right thing- bypass it. Most of the vendors instructions say to do this.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.