We are trying to run an asphalt modified against a field of chevy spec motors with Dart Iron Eagle 200's. We have a lightweight bottom end vs the heavy chevys. My question is our rules only allow the Magnum R/T 7140 head that I cannot find anywhere. Mopar Performance came out with its replacement the P5155469. The problem is we are allowed 180cc head no modifications and the new head is 172cc. the old head was flowed at Shady Dell at 245@ 28in of water. Has anyone flowed these newer performance heads 5469? if im going to petition the tech inspectors to allow me to run the newer head we may have to change pistons to get to the rule 10:1 or cut the heads and manifold to fit. I know im looking for a needle in a haystack looking for the old R/T heads but Im looking.