Last weekend at Sears Point, the Historic Trans Am cars were there in mass. One of the tricks that was pointed out by the host at a Ford oriented Trans AM tech session held during the lunch hour was an Aluminum bellhousing (instead of Cast or Hydo formed Steel) that was disguised with ballistic (bullit proof) fabric and then painted to look like steel. This was from the Bud Moore camp. Quite light and probably effective but not tested
Visually it looked like a cast steel unit.