"o-ringing"

I'm at a point in a project where I need to decide between o-ringing the block or the aluminum heads. What do you guys think would be the better choice, and why?

Thanks in advance,
Shannon

My Block is O-Ringed without grooves in the heads. This allows me to Repair/Mill/Swap Cylinder heads in the future w/o worrying about matching up the grooves to Rings in the block.

Good luck!

I was running an O-ringed block with no grooves in the heads. Worked OK until I got my compression over 14:1 then I had sealing problems. When I groved the heads the problem went away.