torque converter
The torque converter will need to be neutral balanced, meaning no added weights. The factory Magnum flex plate will work, you just have to waller out (is that a word?) One of the flex plate to converter bolt holes.
The only other thing is the diameter of the recess in the crank vs the diameter of the snout on the converter. I know very little about slants.
My example is, for a short time I used a 66 small block converter on a 5.9 Magnum, but used a bushing over the converter snout since the crank recess is larger on newer engines (67 up?) as compared to the diameter of the converter snout of the 66. I also wallered out one of the flex plate to converter bolt holes.
Somebody with slant experience will chime in.