Quote:

These older cars are so flexible that almost any added structure is a noticeable improvement in rigidity.



Years ago my Dart (slant six converted to 340 with a stick) use to flex around so bad from the daily pounding that the floor pan was cracking around the transmission tunnel!

Picked up a set of bars at a swap meet and welded them in place front and rear and the difference was night and day. Had problems getting the car to hook up after that because the body was no longer absorbing the "blow" when letting the clutch fly.