273 torque converter

That 273 convertor, if 66 or older, will not fit the Magnum crank. Well it will but has no nose support and nothing to to keep it spinnining concentrically withe the crank. But
if 67 or newer, then no problem. butas Kendog says, you will need to install the properly weighted flexplate.

But IMO, the 273 2bbl convertor stalls very low, which is fine for a DD, but if yur looking for performance, then now is the time to upgrade.