Not positive about those particular castings.. but I do know of several using afd's versions of the blue thunder stuff. Expensive stuff but huge on power potential. Unless u really want to spin that bottom end really hard/$$$$.. I'd definately lean towards the smaller ports. Wider broader power band will give you higher average power. Plus.. you can always port them later on whereas shrinking too big a port gets tougher to do. Course.. you can just put a larger motor under them and toss more cam at the 4v stuff too. Good luck with it.
I say go for it. Both AFD and CHI have heads tailored to specific displacements and RPM objectives. The Aussies were raised on Clevelands and have really honed their craft when it comes to this head design. I love Clevors and agree with groberts that properly executed, the HP potential is huge. One of the bigger challenges is fitting a set of headers in a Maverick that will compliment the airflow. Even the currently available Windsor headers are very restrictive when paired with many of the aluminum aftermarket heads.
