Th400 & T-case swap 208 to 205?

[SunSoaked]

Swapping a round pattern 205 in place of the stock 208 on an 85. I assumed it was a direct fit but when I stuck them together I realized the adapter needs to be notched for one of the shift rails. With the output/input together and bottomed out there was a 2.5 inch gap which coincides with the adapter width. So am I ok to notch the adapter and bolt it up? Was the factory adapter the same part except for the notch? Disregard the AA adapter in the middle photo I stuck on there while I was experimenting.