starting my 4spd swap tomorrow

Nope. Did you remove a 727 or 904? The 727 is longer than an a body 4 speed and you need a longer shaft for the 4 speed. The 727 uses the same slip yoke as most 4 speeds. B body, C body and truck/van 4 speeds have a longer tailshaft and are the same length as a 727. The 904 is similar in length to an A body 4 speed, but uses a smaller slip yoke.