I agree with everyone the better the air flow the more HP you will make.
A turbo charger increases the density of the air not the air speed, therefore the air speed of a small port is greater than that of a large port and a larger port will flow more air. You just have to be carefull that the air speed does not get too fast. All that said, with FI you can somewhat put the fuel where you want it with a carb you have to control the wet flow if you want the engine to live, with the larger fuel demand of higher HP this becomes a problem.
The talk is the Brazilian head cracks, the thickness of both heads are the same, if you port it out to were is flows good air I believe it would crack easier so I just cleaned my head up and kept the walls as thick as possible and put smaller valves than normal to keep it strong. Since the port enters higher than a stock US head the low lift flow is a little better which will not hurt. Time will tell!
As for as bump ports , stock ports, divided ports, or whatever air flow is air flow. If you know the air flow you know the biggest part of the VE of the engine and the HP potential of the head just multiply the air flow number by the increase in density of the turbo (not the pressure ratio) and you get the max potential of your setup.
I don't think you can ram tune a siamessed port unless the cam is very mild or the valve timming is different for each cyl. or both. Too much for my small brain (just turn up the boost).
Just my thoughts,
Harry
