Larry,
Sorry to see your troubles,
What I see and here from the other's is correct!
One thing missing is that when metal especialy thin wall tubing is ARC welded it becomes brittle. that is why torch welding is superior!
You don't have the problems with embrittlement.
I see that there was a lot of arc welding in this area and your crack seem's to start there.
When your header is repaired and as long as you have not brazed the repair area, have your welder heat the repair area up with a torch till it is cherry red and cover the area tightly with fiberglass blanket's to allow the metal to draw down, this means it will soften & make it less brittle so it can twist and grow without breaking,
Mark
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.