Can I use a 67 904 on a 72 225 or is the crankshaft register hole size a problem?

Again, this was all spelled out for me in the beginning of this post but to reiterate; The crank hole (register) is smaller on the 67 and down and larger on the 68 up slant 6 engines. The "nub" of the converter is small on the 67 and large on the 68 up. The smaller nub fits into the bigger hole (with a spacer) but the bigger nub will not fit into the smaller hole at all (and the converters don't interchange). Therefore the 67/down trans will bolt to the newer engine but the later transmission will not bolt to the earlier engines. Several members here sell an aluminum spacer that slides over the small nub converter to let it ride in the later crank big hole without being sloppy.