360 with 904 pushbutton

I'm wanting to put a 360 in a 1964 Valiant but in order to do so I've got to promise to keep the "cute" pushbutton shifting. Has anyone done a 360 swap and mated to the pushbutton 904? Or, can anyone tell me what all will be involved? I understand that the external balance must be taken into account. (maybe a B&M flex plate 10239?) I also know the early 904 used a different diameter crank pilot hole and shaft splines than 68 or newer. Is there a torque converter that will make this possible? How about swapping out the front of the tranny? Any advice that will help me not go to bed as dumb as I woke up will be greatly appreciated!