Again, I think you're looking at tail-shift parts when you need to look at '73 and beyond side-shift. To do the conversion you essentially need to switch EVERYTHING from the gear shifter on back. So I'm pretty sure you don't need part 14 anymore.
I'd also recommend going ahead and getting Chris' other product for this - the precision shift adjuster for side shift:
Tangerine Racing Transmission/Rear Axle Products.