273 upgrade to 4bbl?

big inlet to small ports has a step that causes more problems than small manifold onto big ports
both cause a disruption to flow.
but the former is caused by the hard step and turbulence caused and the latter is caused by the gas stalling due to change in pressure when moving from the smaller tube to the bigger

if you can be bothered filling the manifold with JB weld or some such from the gasket face back and then blending it to the size of the 273 gasket, would give an excellent taper that smooths the path and increases gas speed into the port in the head.
I think that would keep the speed up and have a positive effect or torque at some of the rpms where it would be robbed by the mismatch.

Dave