64 273 Torque Converter issues

There isn't a whole lot of material to work with on the converter snout since it is made out of stamped steel. What really messes things up is the input shaft spline count changed when the register did (after '67). You can have a converter made with the small register and the higher spline count and vice versa, but be prepared to spend big bucks for a custom converter. It's cheaper to throw in a '68 or newer 318 crank.