I have rechecked all of the measurements on my unknown converter and everything is pointing to a 727 converter. 130 teeth, 1.875" snout etc. but when counting the splines inside. I see that there are two sets of them. I get 27 splines on the top set and 24 splines on the bottom or inner set.

http://www.forabodiesonly.com/mopar/showthread.php?t=332348

I see on the above link that the spline count for the 1967 and later 727 have 24 splines so counting the inner set gives me that.
Does that sound right as the inner set being the one to count?