64 3 sp to 77 4/OD Installation

Ok, Moparians I am having a friend help me with installing a 77 "Feather" Duster 4 speed(yes, I know it's a 3 sp w OD) into my 64 column shift 3 sp Valiant. I have been told it will work. I have a clutch kit, floor hump from Brewers. I started cutting out the floor section and have a few questions.

1) If my measurements are correct the original driveshaft will be too long?
2)Does anyone know if the spline count is the same on the tail shaft(26 spline on the 77).
3)Will the clutch fork from the 64 work?
4) will I be able to clear the frame support that runs over the trans. or does it need to be trimmed.
5)Will the new trans. bolt up to the old support or is there a kit?
6) What else am I missing?

Thanks in advance if you need pics let me know I'm going out to take some now.