I would go with the recommendations of MP and Mancini. Been going there for 20 years and both Art and TJ know what they are talking about. They have been working the counter all of that time.
The heads allow the engine to breath. Some heads give better flow than others. The camshaft grind determines the torque and horsepower curves and shape of the curves. Changing the heads will basically shift the same curve up or down on the graph and will not affect the shape of the curve or the peak horsepower or torque RPM. This means that the camshaft determines the shift points.
The ports in the heads are constant. The camshaft lobe size, shape, ramp curves, and lobe centerline from intake to exhaust make the shape of the curve which affects the shift points. The heads have to flow in the RPM range that the camshaft is designed for.
Make sure your springs are stiff enough for your max RPM so you don't float a valve. Once the valve kisses a piston they don't make up afterwards.
