About the larger exhaust ports:
Something to consider, race prepared 2.6L heads obtain more horsepower by filling in
the exhaust ports some, produces better scavenging.
This is usually done by filling-in the port floor, creating a "D" port exhaust.
Since the intake will obviously be larger on the new head, keeping the exhaust port
the stock size, might produce better results than making it larger...
Look at the I/E port size varience on almost all heads, there is MUCH more I/E varience than on the 2.6L head...
I'm NOT the flow engineer, just want to offer what I know.
I think it's awsome this is actually happening!
Fred