Need yoke for 727 transmission

We tried two different drive shafts and both won't fit the transmission. The 727 output shaft is 1.3" dia. with 30 splines (no master spline). Is this typical for 727 transmissions? The yokes on the test shafts were smaller dia. and had 25 splines with a gap for a master spline. One of the shafts was supposed to have come from a '78 Diplomat cop car (not sure if it's trans. was a 727). The other shaft was supposed to have come from a V8 Duster (trans. missing).