Aluminum vs Cast Iron bell housings

Flywheel for sure on the first one, clutch housing on later one, in either case, a lot of weight to be throwing around. Lost a few 8 3/4"s and driveshafts before I switched to the Dana. The scariest failure was even later when I was making some more significant power, going into 4th gear at 120 something mph, and it broke all four ears off the trans case and the trans rotated and destroyed various other things.