Dave Friedman's excellent book "
Shelby GT40" has photos and text of a crash test that Shelby did on a MkII after Ken Miles accident. It was ran headon into a wall from a speed of 51 mph. The monocoque in the drivers area held up well. What was disturbing was when the front wheel/tire assemblies pushed back against the rocker area (fuel tanks), the increased pressure in the fuel tank(s) popped the filler cap(s) open and fuel (they substituted Stoddard Solvent for gasoline) sprayed over the car like Ole Faithfull. They supposedly changed the design of the fuel bladders. They also talk about an on board fire system but said in those days it was hard to fit one in the car. The article goes on to say that an on board system was fitted in the MkIV's at LeMans in 1967.
A friend recently sent me an url showing a wrecked GT40. Don't know who's GT40 it is, but it's hurt.
http://www.wayupscale.com/galleries/gt40/index.html
Dave