Just spoke to Dave. There were too many issues to make the cast mani work. In order to get the turbo location right, an extension would need to be added to the collector on the stock mani. And once you start adding steel to a cast iron set-up beyond just adding a flange, it just starts to make more sense to build an entire manifold out of SS.
So he has a quantity of header flanges being fabbed as we speak. Everything else is mocked up.
With the holidays coming up, I'm guessing things won't be buttoned up til early to mid January. But with a lot of other family-oriented obstacles shouldering my stress loads, I'm full of patience for the turbo project at this time.
I'll keep the updates coming.