im aware of the ball bearing mod, oil change procedure, etc. my question is about a note made by Gray about having the hole thats frilled into the threads covered. gray said: "It MUST be AT LEAST long enough to completely close off the drain hole that is drilled across the threads, or a loss of oil pressure will result." is this the reason for the allen bolt to be shouldered? if i were to replace the bolt with a hex head, it HAS to be shouldered correct? not just the full length threaded??? or is it ok to have a fully threaded replacement? thanks guys!