[wolfrpi]

I believe the head is actually cut for the O-ring. As far as I know the O-ring is actually placed inside the widefire ring - thus effectively giving you a larger and stronger ring to prevent combustion from escaping the cylinder. BTW - I can not find the turbo papers at the moment - I thought I sent them to you by standard mail a while ago. One way or the other I'll get you the documentation even if we have to call TEC and get a receipt printed again. Good luck,