What are the consideration that governs the choice of profile of a cam?

there are a couple of factors to consider.... the rest of your valvetrain must be compatible with your camshaft (valve springs, heads,carb) by changing your cam profile you are changing the geometry of the valvetrain...more lift on a cam is going to compress your springs more, if they can't handle the amount of lift of the cam they coil bind....select a cam that matches your heads the best then make a carb choice for a good combination