I am a lock-it-down with a bolt guy and one reason beside safety that I use a plan old bolt is the Fumto valve does not allow all the oil to drain in most engines. A few years back was an article on how to modify and file a notch in the threaded end of the valve to allow the last half pint of oil to drain. That fact, the cost and safety issues kept me with my bolt. If I must modify the valve, buy a safety nipple or wire it for safety, I really don't want it.