Cars sounding like sewing machines....that can't be good! Maybe the lifters are hoping off the cam lobe just a tiny bit.

 

No, the sewing machine noise is normal. Imagine an indiana jones sound effect when somebody pulls a sword from a sheath. Now imagine that sliding noise many time a second, but quitely coming from under your valvecovers. Thats the sewing machin noise. Most suspect that its due to the valves sliding in their guides faster because of the accelerated ram rates of the cam. Its perfectly normal for medium to big cams.