Couple of questions about my 1973 340.
Flywheel? Is this a manual shift car? Also, since you are using a 904, is it the original 904 to the 66 cuda? There is a difference in the diameter of the pilot snout of the converter of a 66 and earlier 904 and a 67 and later unit! You need to make sure you are apples to apples on this, as the register on the 340 will be the larger diameter and will not work with the earlier converter!!
More info please!! Geof