yeah but they still have the same large outter flywheel pilot ring, so just grind out the inner diameter convertor register of the early 273 crank for the later convertor snout.
fwiw
Maybe machine it on a lathe or center drill it somehow but there would be no way to use a hand grinder and keep the hole centered. If it isn't centered, it will vibrate. It would be better to just have a convertor made to fit.