I was just on the old forum and saw a link to this topic. Please note that Dove does cast aluminum TP heads and that they are available with two different Dove-design exhaust runner layouts. I did a series of articles for, if I remember properly, Mustang Illustrated Magazine, regarding the use of a set of these Dove heads with his 'type II' exhaust. With this design, the exhaust runners are raised, reshaped, and spread apart. We put this combination in Brother Lon's '67 Mustang.
It was necessary to remove the 'shock towers' and go to a coil-over lay-out in order to allow room for the required custom headers. That design made it possible to come straight off the heads, without any turn-down, for more than six inches. I have my copies of the articles in question somewhere in storage, so I can't give the flow figures from Wayne Kuchtyn's Superflow, but there was significantly greater flow available with the alternate design. I'm practically sure that the flow ratio was very close to 80%.
KS