727 or 904 converter?

How do you ID a torque converter to determine if it's for a 727 or a 904 trans?

IIRC the 727's keyed imput "lug" is 1.875" in diameter, the 904's is smaller.

I have read where the spline count is different between the two. I'm wondering if that is also away to ID them.

The 727 converter snout is 1.875" in diameter and the 904 converter snout is 1.5".

Diameters and spline count in this thread:

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

Using the snout diameter method. I find that it is 1.875" dia. What I have is a 727 conveter and I was thinking that it was a 904 one.
Thanks...

If you don't have anything to measure with, count the ring gear teeth...727 has 130, 904 has 122. (except for the '60-'61)

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?

Yes, the outer splines (reaction shaft) were the same from day one to the end of production...only the input shaft (inner) splines changed over the years

Thanks, John. I knew that you would come through on this....