You can get the adapters for about $200- $250. A lot of machine shops will make them for you cheaper than you can order one.
The 208 are not as bad as people say they are, but the 205 is a lot tougher. I've run over 1,200hp through one with a trans brake set on 5,200.
208's are 2.61 low gear and the 205's are 1.98 in if that matter s to you.