A904 front planetary and washer question

If I had a 66up donor could the output shaft and everything on it be put in the 64 case? No response from AandA yet. I'll give them a call tomorrow. I've seen both sizes of washers but only the 4 pinion planets in two ring gear sizes. Almost bought one with the ring gear and washer from Cobra but decided it wasn't the right one. Overdrive would be nice. How much trouble would that be in my dart?