It's actually pretty straightforward- they came on 318s and V6s, so it has a standard small block bolt pattern, no adapters needed. It still uses a standard '66 and later 904 slip yoke, and the driveshaft stays the same length as with a 904. Naturally if you're putting it in a '65 or earlier A, you need to ditch the ball & trunnion shaft and get a suitable slip yoke shaft. I used the B&M 10239 flexplate to bolt the stock torque convertor (neutral balance) up to a 360. Not an ideal convertor for optimum performance, but it suits my purposes on my wagon (cruiser). On my '66, I used the shift and kickdown levers off the old '66 904 and bolted it up to the stock column linkage. The 999/32RH lockup is all hydraulically controlled (no electronic or pressure controllers needed like on the later OD transmissions), with just a lockout for the convertor lockup (the tow/haul button on the original truck application) that can be wired to a simple on/off button or toggle.
It uses a typical late model speedo drive, so on the early A you need to run a '66-'67 cable (threaded ferrules on both ends) in order to drive the early speedo, especially if you're replacing the one piece '65 and earlier cable. A standard cable works on later As.
For the cooler lines I cheated and used brass 45* fittings coming out of the trans, I just couldn't make sharp enough bends in that tiny tunnel without kinking them- there's just not much room with the shift/kickdown linkage and speedo cable all crammed into the same real estate... :)
The good news is, I'm looking at doing the same swap into my '75 Dart, and there's LOTS more room in there- doesn't look like I'll have to grind the tailshaft ribs at all, and mucho more room for the linkage/lines and such.