[RPM427]

To port the stock intake is a lot of work. It is not worth it most of the time, but if you really want to do here is a breif description how.

To port the lower you can run a bead of weld along the top of the intake tract. That gives you more materail to remove from the inside. Now you need to gasket match the intake to your heads. There are lots of articles online explaining that.
If you still have stock heads, porting your intake will not improve performance, the stock heads are the bottle neck.

To port the upper, cutting it in half is only way top do it right. That way you can access the ports inside the intake. Edelbrock is nice enough to make an access cover on thier intakes for this purpose. This is alot of work becase you need to be able to weld it back together.

You have to make sure you removed the same amount of material from each intake tract otherwise is will not be balanced. You will also need to match up the upper and lower tracts perfectly and then make a new larger gasket. Or design the intake tracts to fit a truck/holley upper-to-lower gasket/spacer.