65 A body transmission?

I'm pretty sure the 65 B-body small block cars with a cable shifted, slip yoke transmission.....are 727 transmissions. Why else would the tailshaft unbolt off that transmission, and bolt up to a big block 727? My old 64 Belvedere wagon came with a 318 Poly motor, and a pushbutton small block 727. I'll have to see a 65 904 with factory. cable shift and a slip yoke before I believe it.