How much money is your customer willing to spend on the cam and valvetrain? Is it a budget build that will require a flat tappet cam with solid or hydraulic lifters, or is the sky the limit? What kind of vehicle is the engine going into (light car, heavy car, truck, race car)? What kind of transmission and gearing will the vehicle have (stick, automatic, wide ratio or close ratio transmission gearing, final drive ratio)? Are you building an engine for everyday driving? For towing? For street performance? For street/strip? For drag racing or a circle track car? Are there class rules that limit the type of camshaft and valvetrain components that are allowed?