It doesn't always work. Case in point, a friend has a Mustang, totally certified, Big Blk ford. Christie Wright was standing outside the fence by the burnout box at Twin Cities La. Rodney Jorden had everything certified including a lined bell housing PG on the B/blk Ford. During the burnout the flywheel came apart, went thru the fence and severly injured Christie, it cut the chassis in half and put Christie in the Hospital where she lost 1 finger and a thumb, it also went very deep into her leg, luckly EMT was able to get her to a Hosp. in time to stop the bleeding and she is now O'K. Certifaction is good but it doesn't always make accidents un avoidable. I'm friends with both, and Christie is O'K and back at the track. Bottom line, there is nothing , certified or not that is totally safe. You can read Christis story at Twin Cities drag track, forums
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