I've seen the used bolts sell on ls1tech before...figured I'd post them up before throwing them out *shrug*....dunno why people buy/bought used ones...but it's happened haha.

The LY6 pistons do have valve reliefs. Found this on ls1tech, "the dish have a diameter of 3" and a depth of 0.050 so .35cu in.. in cc(cubic centimeter?) 5.78cc
So around 6cc + 2cc for the notch... -8cc piston..".