DanCouga wrote:I think I have read that VQ35 has a larger combustion chamber, so that would lower your compression ratio.
You're correct. If you were to put vq35 heads on a vq30, it would give you a CR of about 8.5:1 which would be awesome for boost, but it would suck for NA. If you wanted to stay NA you'd have two choices. Get high comp vq30 pistons or buy these heads. These heads are basically vq35 heads with vq30 combustion chambers. You also would have to use the vq35 IM setup if you used the vq35 heads.