port matching the intake manifold?

The speed of the air and fuel at the heads entrance at the intakes exit is at max speed and isn't slowing down enuff to cause any problems after the air and fuel enter the head. It's more of the turn that will create a problem than the port size difference. Not to mention the valve itself getting in the way from stem to head. Fuel will gather/puddle there a hundered times more than a port size change.

Gasket matching is good. Like said above, not larger than the cylinder heads entrance. That would create a damn. (Double meaning.) As in damn I screwed up and a damn for holding the air and fuel back in a puddle. The damn will create a spot for the fuel to puddle and drip in drops.)