Ex850R And on the NA TB is has a plastic thing rivettedon,you take it off and silver solder the holes.
Option 1. Remove plastic thing from butterfly and silver solder holes
Option 2. Remove butterfly and fit one from a 960.
Option 3. The easiest option, Leave the plastic thing there, knowing it could be costing you .5% of your airflow at full throttle but gaining a nicer feeling throttle at light pedal.
I went with option 1 but if I was doing it again I would have no issue going with option 3
BTW, here is a pic that shows a turbo manifold opening on the right, and a ported turbo manifold on the left, the NA manifold opening is very similar in size to left one. The retaining bolts for the throttle are identical, meaning it is a bolt on modification once the hole is big enough.