Interesting, I measured a 19" and my 22" and both are 24 1/2" to where the shroud bolts on. so the width of the shroud is the same, question is would the fan hole be the same? I have both radiators but no shroud so I can't say.
If no 19" radiators were used that sums it up, but the moparts radiator numbers thing says the 1970 6 cylinder E body used a 22" and the 1970 non A/C 318 and 340 used a 19". this makes no sense so maybe that's a screw up.