I made significant progress on the swap today! Started removing the Powerglide yesterday at noon and was driving the 700r4 by 3pm today.
Driveshaft: My Powerglide was 25" and the 700r4 was 30" so I cut my driveshaft 5" and bought a U-Joint that fit on the original drive shaft yoke and the new 700r4 yoke.
Linkage: I ended up doing my own fabrication and keeping the original linkage. I had to make my own bracket to connect the two. Check out the pix. It looks a little 'back wood' but it shifts smoothly and it was $ friendly. Minor welding involved. However it seems that my column doesn't allow me to shift all the way down to 1st gear. Does anyone know how to fix this?
Wiring: I haven't finished the wiring. I'm having a little trouble installing a switch that uses the brake pedal to un-activate. Is it really necessary? I read all I had to do was connect the A pin to a constant ignition 12v power supply?
I had to install some spacers on my transmission mount because it made my engine drop from the back and I couldn't install my HEI distributor back in (I removed to easily unbolt the top bell-housing bolts).
Here are some pix of my old Powerglide, new 700r4, fabricated bracket & install:
Fabricated 'back wood' bracket: