You have several options:
1. previously mentioned swap out the front internals on your 904 to accept 68 and new converters and then buy a new 360 converter.
2. custom converter with large nose hub to fit the 67 and earlier 904.
3. Use a 68 and later 904 with the Imperial Services conversion kit (new shifter cable and minor mod to the valve body) which allows you to continue to use your stock 65 shifter (am going with this approach with my 340/904 conversion in my 65 GT 'vert).
4, Use a 68 and later 904 and either aftermarket cable operated shifter or 66 and up stock rod shifter and console (console is a really tight squeeze between the stock 65 seats - did this mod years ago).
5. Use a stock 67 - earlier converter with neutral balance flexplate.
