i had a sfi issue one day in columbus,oh. the drive train was a blown hemi on 50 percent. bruno convert/lenco three speed. the fly wheel was a ati. i had 1/2" bolts going from the converter to flywheel grade eight lock tighted. duing the burnout the bolts broke. anyone who has raced at columbus knows how far away the stands are on the right side of the track. the bolts hit the track and flew over the wall over the grass over the return road and up to the top rows of the stands. a guy was sitting there with a camera around his neck. one bolt went through the lense and out the back destroying the camera. the bolt hit his leg and burned it slightly. needless to say when i got back to the pits the nhra golf carts were already there. they inspected the car. all sfi stickers were there on flywheel and bell housing. they asked why there was no cover on the bottom of the bell housing and i told them they dont come with one and i cant modify it due to your rules. nothing came of it. so you can have all sfi parts and still have a on track incident. about the same time my friend with a similiar set up had the same problem. we both went to 5/8 bolts and never had a problem again. at the grove years ago a fuel dragster blew a clutch and pieces flew into the crowd killing three. my friends hemi gtx blew a clutch and parts went through the headers and floor. i was driving the original candies and hughes 65 funny car and rolled a sprag in the 727 when it blew parts went through the dash and frame and right side front fender and it had a shield on it. removal was easy we pulled the drive shaft and it just fell out. when they first asked me to drive the car i told them i wont unless it had a shield. good thing i did.