Who here runs an O-Ringed block? Leaking head gasket problem!

I've run O rings with cheap gaskets.. You don't need a "certain" gasket. The trick is that the O ring HAS to sit behind the fire ring. I've also only grooved just the block like 1000's of others without issue,so I don't see where grooving both comes into play unless under the most extreme of circumstances, plus you don't need to fill in the block when you remove the rings, why would you??? If the fire ring is in front of the O ring, then whats going to leak through the groove???