I'd go with the 70 & fab a shifter. this'll give you the slip yoke so you would need that yoke & may or may not have to shorten the shaft. Use the '70 TC (cant use the 64 TC with the 70 904) & you wont have to buy the ring for the TC nub needed with the 64 TC/360 crank pilot hole combo (pattys TF's if ever needed iirc). Not aure if '70 has the PTK or not, a desireable feature. HOWEVER just me if I had a 64 pb vehicle and a 64 PB trans I would stick with that, looks neat looks original no added floor shifter which I dont care for their looks/clutter