Do I need an SFI bellhousing?

Has anyone ever heard of a flywheel or clutch coming apart on a slower 12 or 13 second car? I never really considered an SFI bell housing, how likely is an explosion?Is it RPM based or massive torque with sticky tires that rip it apart?

Was in a friends Road Runner years ago....on the street.....when his let loose. Nobody got hurt. It ended up entering thru the floor and leaving thru the windshield....Car had a stockish 440 in it...