I have not tried to really open up the revised MR casting. With the CNC chamber and the port "as cast" we are getting into the middle 360s at .700 - so a 385 target for a ported out version is not out of the question. The exhaust port on both MR and HR heads is raised .400 - that translates to .200 "up" and .200 "out".
The Victor can be ported to match the MR head without welding. We recently ran a port matched Victor and unported BT MR heads on a 12:1 482 that made 729HP - so they will make good power.
