I contacted Chad Speier of Speier Racing heads, http://www.speierracingheads.com/ and he has agreed to help me or any one else on the BBB heads including your the Stage 2,3, and 4 to make them flow better. (Meaning VE, Volume of air, Port velocity and so on) He looked in to a set not to long ago and seen it was hurtin in the port velocity area and he said he can inprove on it. I'll let you read his front page and see if you want to contact him to help build a better head in the futher for the monster cubic inches.600+ . I just want to help much as possible and don't want any notariety from it. Thank you Gary Mc.