Depends on a lot of things, one being the combo.
If the heads flow at or below the 260cfm rating of that particular intake, then maybe not, because all you'll be doing in a sense is allowing in more air but at a slower pace/velocity.
When you open/widen/enlarge an air passage, like in a head/intake runner, the air slows down some.
A good example is when people gasket port match their intake and heads port window, all they are doing is creating this hour glass effect-plenum-runner-port going from a larg plenum area -then bottle necking down through the runner-then opening up again at the manifold exit/port window just to immediately taper off and squeeze by the push rod pinch.
So if they pinch only flows x amount, and widening/enlarging slows things down 'enough', I would say as long as you have the same x amount flowing through both head/intake manifold, I wouldn't really be too concerned or be looking for more than the head will move 'at sacrifice of torque producing velocity'.
I myself NEVER gasket match the push rod pinch side of the port windows, only the roof/floor/divider.
The pinch is the law with sb iron, so why bottle neck into the inevitable?
I know this is more around your question than head on answering it, so in a nut shell with the above in mind, unless the heads flow more than 260cfm, don't bother with the ported intake, I would maybe have some plenum work/blending done and open the windows up only to what you have now.
If the heads you have now are opened up to the gaskets already, well...it is what it is.
