Had the same problem. MSD makes two different tach adapters. an 8910 and an 8920.
There is speculation which is one is correct. I believe that different distributors may require one or the other.
Anyway...I went with the 8910, for my Malorry Unilite Distributor. All works well. Go to the MSD website for a complete overview.
Tom
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.