Generation IV Internal Engine - diamond piston part # for 6.0L LQ4 pistons?

I am wanting to make sure I get the correct pistons. I have an LQ4 that is bored .30 over. I need a piston with valve reliefs. I was told diamond has them. I have a set of ls3 heads I will be putting on the 6.0L so I want to make sure they have reliefs in the pistons to avoid PTV.

is this a correct part number before I order them?

Diamond part # 11515


If so, it says my compression ratio is going to be 8.9 with the 70cc ls3 heads. That is way to low I think. Thoughts?

Call SDPC and talk to them. Here are your choices.

http://sdparts.com/category/diamond-ls1-flat-top-pistons