Retarding the cam will usually help 1/4 mile times. It shifts the power band up so the car will pull harder at high rpm's, but you will be sacrificing low end torque. For a car mainly driven on the street I would leave it alone, especially with a vert. Also, whenever you change cam timing you should check piston to valve clearance. Seems like a lot work just to pick up a few hp if your engine's already built.