torque converter troubles

The 67 on down 904's use a course input spline, I think it's 18 splines. The 68 on up 904's use a 24 or 27 spline count on the input shaft. I have a 67 904 in my barracuda and changed the input shaft to a 68 on up shaft. The reason being there are no high stall converters for the 67 on down 904's. Looks like you have to remove the trans. If you change the input you'll have to change the input drum also. The Mopar converters do not fit 67 down 904's. Hope this helps you. Bob