The TH400 kit is made from three pieces:

The TH400 kit is made from three pieces: The fig. 8 bolt pattern is welded to the ring, and then machined flat. The ring that is welded to the 203 plate has a dia. of 7.5". With this diameter the ring is aprox. 1" from the bolt circle. Providing a very strong adapter.

The TH400 doubler kit has an oil seal included and installed to keep the fluids separate. There is also a vent hole with a 1/8" pipe to barb fitting included. This is for the venting of the NP203 only.

The cost for this adapter is $540 if your wanting your stock 203 shaft resplined.

If your wanting a new billet 8620 shaft with the adapter, cost is $670.  I can set the rotation of your 205 to what you want... But the two most popular is either stock or up 2" or 12 degrees...