On a stock motor the intake is not the power restriction, it is the valve springs. If you updated the valve train to shaft rockers and upgraded the cam and valve springs, then the intake would be a restriction at higher rpms (+4,500 rpm). You can modify the stock cast iron manifold to gain another 20 or so hp.
The problem with the Edelbrock is uneven distribution between cylinders. Cadco supposedly fixes this by porting some areas to even out the flow distribution to gain some lost hp. If you are running on the cusp of tuning to get max hp, then the uneven distribution of fuel and air is problematic.